diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3dc19cf..2b732eb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -40,6 +40,7 @@ For more information about each release including git tags and artifacts, see [R
 - Add retention limits to Kafka topics to prevent unbounded disk growth ([#249](https://github.com/roostorg/osprey/pull/249) by [@VINODvoid](https://github.com/VINODvoid))
 - Fix failed UDF query ([#233](https://github.com/roostorg/osprey/pull/233) by [@chimosky](https://github.com/chimosky))
 - Force a visible scrollbar on the event-stream virtualized list, which was relying on the OS auto-hide default and was easy to miss ([#367](https://github.com/roostorg/osprey/pull/367) by [@julietshen](https://github.com/julietshen))
+- Show the event-stream timezone once instead of twice; `zz` rendered a doubled abbreviation (e.g. `EDTEDT`) after the moment-to-dayjs migration ([#419](https://github.com/roostorg/osprey/pull/419) by [@julietshen](https://github.com/julietshen))
 
 ## [1.0.1] - 2026-02-27
 
diff --git a/osprey_ui/src/Constants.tsx b/osprey_ui/src/Constants.tsx
index f338a58..7e9769a 100644
--- a/osprey_ui/src/Constants.tsx
+++ b/osprey_ui/src/Constants.tsx
@@ -13,7 +13,7 @@ export const Routes = {
   BULK_ACTION: '/bulk-action',
 };
 
-export const DATE_FORMAT = 'M/D/YYYY h:mm:ssa zz';
+export const DATE_FORMAT = 'M/D/YYYY h:mm:ssa z';
 
 // These should mirror the `--status-primary` colors in Colors.module.css
 export const StatusColors = {
diff --git a/osprey_ui/src/utils/DayjsSetup.tsx b/osprey_ui/src/utils/DayjsSetup.tsx
index 66672b7..1abe135 100644
--- a/osprey_ui/src/utils/DayjsSetup.tsx
+++ b/osprey_ui/src/utils/DayjsSetup.tsx
@@ -1,4 +1,5 @@
 import dayjs from 'dayjs';
+import advancedFormat from 'dayjs/plugin/advancedFormat';
 import customParseFormat from 'dayjs/plugin/customParseFormat';
 import duration from 'dayjs/plugin/duration';
 import timezone from 'dayjs/plugin/timezone';
@@ -8,3 +9,5 @@ dayjs.extend(utc);
 dayjs.extend(timezone);
 dayjs.extend(duration);
 dayjs.extend(customParseFormat);
+// advancedFormat provides the `z` timezone-abbreviation token used by DATE_FORMAT.
+dayjs.extend(advancedFormat);