diff --git a/.betterer.results b/.betterer.results
index eb828ff66ac..f9f719bfc49 100644
--- a/.betterer.results
+++ b/.betterer.results
@@ -7416,8 +7416,7 @@ exports[`better eslint`] = {
     ],
     "public/app/plugins/datasource/prometheus/querybuilder/state.test.ts:5381": [
       [0, 0, 0, "Unexpected any. Specify a different type.", "0"],
-      [0, 0, 0, "Unexpected any. Specify a different type.", "1"],
-      [0, 0, 0, "Unexpected any. Specify a different type.", "2"]
+      [0, 0, 0, "Unexpected any. Specify a different type.", "1"]
     ],
     "public/app/plugins/datasource/prometheus/querybuilder/state.ts:5381": [
       [0, 0, 0, "Do not use any type assertions.", "0"]
diff --git a/public/app/features/alerting/unified/utils/__snapshots__/rule-form.test.ts.snap b/public/app/features/alerting/unified/utils/__snapshots__/rule-form.test.ts.snap
new file mode 100644
index 00000000000..91d24e856b6
--- /dev/null
+++ b/public/app/features/alerting/unified/utils/__snapshots__/rule-form.test.ts.snap
@@ -0,0 +1,59 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`formValuesToRulerGrafanaRuleDTO should correctly convert rule form values 1`] = `
+Object {
+  "annotations": Object {
+    "description": "",
+    "runbook_url": "",
+    "summary": "",
+  },
+  "for": "5m",
+  "grafana_alert": Object {
+    "condition": "A",
+    "data": Array [],
+    "exec_err_state": "Error",
+    "no_data_state": "NoData",
+    "title": "",
+  },
+  "labels": Object {
+    "": "",
+  },
+}
+`;
+
+exports[`formValuesToRulerGrafanaRuleDTO should not save both instant and range type queries 1`] = `
+Object {
+  "annotations": Object {
+    "description": "",
+    "runbook_url": "",
+    "summary": "",
+  },
+  "for": "5m",
+  "grafana_alert": Object {
+    "condition": "A",
+    "data": Array [
+      Object {
+        "datasourceUid": "dsuid",
+        "model": Object {
+          "expr": "",
+          "instant": false,
+          "range": true,
+          "refId": "A",
+        },
+        "queryType": "query",
+        "refId": "A",
+        "relativeTimeRange": Object {
+          "from": 900,
+          "to": 1000,
+        },
+      },
+    ],
+    "exec_err_state": "Error",
+    "no_data_state": "NoData",
+    "title": "",
+  },
+  "labels": Object {
+    "": "",
+  },
+}
+`;
diff --git a/public/app/features/alerting/unified/utils/rule-form.test.ts b/public/app/features/alerting/unified/utils/rule-form.test.ts
new file mode 100644
index 00000000000..adeae48e409
--- /dev/null
+++ b/public/app/features/alerting/unified/utils/rule-form.test.ts
@@ -0,0 +1,36 @@
+import { PromQuery } from 'app/plugins/datasource/prometheus/types';
+
+import { RuleFormValues } from '../types/rule-form';
+
+import { formValuesToRulerGrafanaRuleDTO, getDefaultFormValues } from './rule-form';
+
+describe('formValuesToRulerGrafanaRuleDTO', () => {
+  it('should correctly convert rule form values', () => {
+    const formValues: RuleFormValues = {
+      ...getDefaultFormValues(),
+      condition: 'A',
+    };
+
+    expect(formValuesToRulerGrafanaRuleDTO(formValues)).toMatchSnapshot();
+  });
+
+  it('should not save both instant and range type queries', () => {
+    const defaultValues = getDefaultFormValues();
+
+    const values: RuleFormValues = {
+      ...defaultValues,
+      queries: [
+        {
+          refId: 'A',
+          relativeTimeRange: { from: 900, to: 1000 },
+          datasourceUid: 'dsuid',
+          model: { refId: 'A', expr: '', instant: true, range: true } as PromQuery,
+          queryType: 'query',
+        },
+      ],
+      condition: 'A',
+    };
+
+    expect(formValuesToRulerGrafanaRuleDTO(values)).toMatchSnapshot();
+  });
+});
diff --git a/public/app/features/alerting/unified/utils/rule-form.ts b/public/app/features/alerting/unified/utils/rule-form.ts
index cdd336af723..ca53a5299d8 100644
--- a/public/app/features/alerting/unified/utils/rule-form.ts
+++ b/public/app/features/alerting/unified/utils/rule-form.ts
@@ -14,8 +14,10 @@ import { getNextRefIdChar } from 'app/core/utils/query';
 import { DashboardModel, PanelModel } from 'app/features/dashboard/state';
 import { ExpressionDatasourceUID } from 'app/features/expressions/ExpressionDatasource';
 import { ExpressionQuery, ExpressionQueryType } from 'app/features/expressions/types';
+import { PromQuery } from 'app/plugins/datasource/prometheus/types';
 import { RuleWithLocation } from 'app/types/unified-alerting';
 import {
+  AlertDataQuery,
   AlertQuery,
   Annotations,
   GrafanaAlertStateDecision,
@@ -101,7 +103,7 @@ export function formValuesToRulerGrafanaRuleDTO(values: RuleFormValues): Postabl
         condition,
         no_data_state: noDataState,
         exec_err_state: execErrState,
-        data: queries,
+        data: queries.map(fixBothInstantAndRangeQuery),
       },
       for: evaluateFor,
       annotations: arrayToRecord(values.annotations || []),
@@ -382,3 +384,22 @@ export function getIntervals(range: TimeRange, lowLimit?: string, resolution?: n
 
   return rangeUtil.calculateInterval(range, resolution, lowLimit);
 }
+
+export function fixBothInstantAndRangeQuery(query: AlertQuery) {
+  const model = query.model;
+
+  if (!isPromQuery(model)) {
+    return query;
+  }
+
+  const isBothInstantAndRange = model.instant && model.range;
+  if (isBothInstantAndRange) {
+    return { ...query, model: { ...model, range: true, instant: false } };
+  }
+
+  return query;
+}
+
+function isPromQuery(model: AlertDataQuery): model is PromQuery {
+  return 'expr' in model && 'instant' in model && 'range' in model;
+}
diff --git a/public/app/plugins/datasource/prometheus/querybuilder/state.test.ts b/public/app/plugins/datasource/prometheus/querybuilder/state.test.ts
index b0caa8c9f01..e8bdc3762e9 100644
--- a/public/app/plugins/datasource/prometheus/querybuilder/state.test.ts
+++ b/public/app/plugins/datasource/prometheus/querybuilder/state.test.ts
@@ -1,11 +1,13 @@
 import { CoreApp } from '@grafana/data';
 
+import { PromQuery } from '../types';
+
 import { QueryEditorMode } from './shared/types';
 import { changeEditorMode, getQueryWithDefaults } from './state';
 
 describe('getQueryWithDefaults(', () => {
   it('should set defaults', () => {
-    expect(getQueryWithDefaults({ refId: 'A' } as any, CoreApp.Dashboard)).toEqual({
+    expect(getQueryWithDefaults({ refId: 'A' } as PromQuery, CoreApp.Dashboard)).toEqual({
       editorMode: 'builder',
       expr: '',
       legendFormat: '__auto',
@@ -25,6 +27,19 @@ describe('getQueryWithDefaults(', () => {
     });
   });
 
+  it('should not set both instant and range for Prometheus queries in Alert Creation', () => {
+    expect(
+      getQueryWithDefaults({ refId: 'A', range: true, instant: true } as PromQuery, CoreApp.UnifiedAlerting)
+    ).toEqual({
+      editorMode: 'builder',
+      expr: '',
+      legendFormat: '__auto',
+      range: true,
+      instant: false,
+      refId: 'A',
+    });
+  });
+
   it('changing editor mode with blank query should change default', () => {
     changeEditorMode({ refId: 'A', expr: '' }, QueryEditorMode.Code, (query) => {
       expect(query.editorMode).toBe(QueryEditorMode.Code);
diff --git a/public/app/plugins/datasource/prometheus/querybuilder/state.ts b/public/app/plugins/datasource/prometheus/querybuilder/state.ts
index 17d2d8e5931..0215bec27ea 100644
--- a/public/app/plugins/datasource/prometheus/querybuilder/state.ts
+++ b/public/app/plugins/datasource/prometheus/querybuilder/state.ts
@@ -56,5 +56,11 @@ export function getQueryWithDefaults(query: PromQuery, app: CoreApp | undefined)
     }
   }
 
+  // Unified Alerting does not support "both" for query type – fall back to "range".
+  const isBothInstantAndRange = query.instant && query.range;
+  if (app === CoreApp.UnifiedAlerting && isBothInstantAndRange) {
+    result = { ...result, instant: false, range: true };
+  }
+
   return result;
 }