diff --git a/public/app/features/dashboard/state/PanelQueryState.ts b/public/app/features/dashboard/state/PanelQueryState.ts
index 45a0891a9ff..38d4948ad4a 100644
--- a/public/app/features/dashboard/state/PanelQueryState.ts
+++ b/public/app/features/dashboard/state/PanelQueryState.ts
@@ -274,6 +274,8 @@ export class PanelQueryState {
 
     return {
       state: done ? LoadingState.Done : LoadingState.Streaming,
+      // This should not be needed but unfortunately Prometheus datasource sends non DataFrame here bypassing the
+      // typings
       series: this.sendFrames ? getProcessedDataFrames(series) : [],
       legacy: this.sendLegacy ? translateToLegacyData(series) : undefined,
       request: {