diff --git a/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/helpers.test.tsx b/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/helpers.test.tsx
new file mode 100644
index 00000000000000..2758625c0d4af1
--- /dev/null
+++ b/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/helpers.test.tsx
@@ -0,0 +1,35 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { showInitialLoadingSpinner } from './helpers';
+
+describe('helpers', () => {
+  describe('showInitialLoadingSpinner', () => {
+    test('it should (only) show the spinner during initial loading, while we are fetching data', () => {
+      expect(showInitialLoadingSpinner({ isInitialLoading: true, isLoadingSignals: true })).toBe(
+        true
+      );
+    });
+
+    test('it should STOP showing the spinner (during initial loading) when the first data fetch completes', () => {
+      expect(showInitialLoadingSpinner({ isInitialLoading: true, isLoadingSignals: false })).toBe(
+        false
+      );
+    });
+
+    test('it should NOT show the spinner after initial loading has completed, even if the user requests more data (e.g. by clicking Refresh)', () => {
+      expect(showInitialLoadingSpinner({ isInitialLoading: false, isLoadingSignals: true })).toBe(
+        false
+      );
+    });
+
+    test('it should NOT show the spinner after initial loading has completed', () => {
+      expect(showInitialLoadingSpinner({ isInitialLoading: false, isLoadingSignals: false })).toBe(
+        false
+      );
+    });
+  });
+});
diff --git a/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/helpers.tsx b/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/helpers.tsx
index 551850fa610dbd..27ee5521460928 100644
--- a/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/helpers.tsx
+++ b/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/helpers.tsx
@@ -76,3 +76,17 @@ export const getSignalsHistogramQuery = (
     },
   },
 });
+
+/**
+ * Returns `true` when the signals histogram initial loading spinner should be shown
+ *
+ * @param isInitialLoading The loading spinner will only be displayed if this value is `true`, because after initial load, a different, non-spinner loading indicator is displayed
+ * @param isLoadingSignals When `true`, IO is being performed to request signals (for rendering in the histogram)
+ */
+export const showInitialLoadingSpinner = ({
+  isInitialLoading,
+  isLoadingSignals,
+}: {
+  isInitialLoading: boolean;
+  isLoadingSignals: boolean;
+}): boolean => isInitialLoading && isLoadingSignals;
diff --git a/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/index.tsx b/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/index.tsx
index 29aaa951ff71af..4de471d6733cf5 100644
--- a/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/index.tsx
+++ b/x-pack/legacy/plugins/siem/public/pages/detection_engine/components/signals_histogram_panel/index.tsx
@@ -23,7 +23,7 @@ import { InspectButtonContainer } from '../../../../components/inspect';
 import { useQuerySignals } from '../../../../containers/detection_engine/signals/use_query';
 import { MatrixLoader } from '../../../../components/matrix_histogram/matrix_loader';
 
-import { formatSignalsData, getSignalsHistogramQuery } from './helpers';
+import { formatSignalsData, getSignalsHistogramQuery, showInitialLoadingSpinner } from './helpers';
 import * as i18n from './translations';
 
 const DEFAULT_PANEL_HEIGHT = 300;
@@ -54,7 +54,6 @@ interface SignalsHistogramPanelProps {
   from: number;
   query?: Query;
   legendPosition?: Position;
-  loadingInitial?: boolean;
   panelHeight?: number;
   signalIndexName: string | null;
   setQuery: (params: RegisterQuery) => void;
@@ -75,7 +74,6 @@ export const SignalsHistogramPanel = memo<SignalsHistogramPanelProps>(
     query,
     from,
     legendPosition = 'right',
-    loadingInitial = false,
     panelHeight = DEFAULT_PANEL_HEIGHT,
     setQuery,
     signalIndexName,
@@ -86,7 +84,7 @@ export const SignalsHistogramPanel = memo<SignalsHistogramPanelProps>(
     title = i18n.HISTOGRAM_HEADER,
     updateDateRange,
   }) => {
-    const [isInitialLoading, setIsInitialLoading] = useState(loadingInitial || true);
+    const [isInitialLoading, setIsInitialLoading] = useState(true);
     const [defaultNumberFormat] = useUiSetting$<string>(DEFAULT_NUMBER_FORMAT);
     const [totalSignalsObj, setTotalSignalsObj] = useState<SignalsTotal>(defaultTotalSignalsObj);
     const [selectedStackByOption, setSelectedStackByOption] = useState<SignalsHistogramOption>(
@@ -124,10 +122,16 @@ export const SignalsHistogramPanel = memo<SignalsHistogramPanelProps>(
     const formattedSignalsData = useMemo(() => formatSignalsData(signalsData), [signalsData]);
 
     useEffect(() => {
-      if (!loadingInitial && isInitialLoading && !isLoadingSignals && signalsData) {
+      let canceled = false;
+
+      if (!canceled && !showInitialLoadingSpinner({ isInitialLoading, isLoadingSignals })) {
         setIsInitialLoading(false);
       }
-    }, [loadingInitial, isLoadingSignals, signalsData]);
+
+      return () => {
+        canceled = true; // prevent long running data fetches from updating state after unmounting
+      };
+    }, [isInitialLoading, isLoadingSignals, setIsInitialLoading]);
 
     useEffect(() => {
       return () => {
diff --git a/x-pack/legacy/plugins/siem/public/pages/detection_engine/detection_engine.tsx b/x-pack/legacy/plugins/siem/public/pages/detection_engine/detection_engine.tsx
index d854c377e6ec86..ff6722840fd6b2 100644
--- a/x-pack/legacy/plugins/siem/public/pages/detection_engine/detection_engine.tsx
+++ b/x-pack/legacy/plugins/siem/public/pages/detection_engine/detection_engine.tsx
@@ -177,7 +177,6 @@ const DetectionEnginePageComponent: React.FC<DetectionEnginePageComponentProps>
                             deleteQuery={deleteQuery}
                             filters={filters}
                             from={from}
-                            loadingInitial={loading}
                             query={query}
                             setQuery={setQuery}
                             showTotalSignalsCount={true}