diff --git a/src/routes/plans/+page.svelte b/src/routes/plans/+page.svelte
index 42a5e15ee0..e8229ddf69 100644
--- a/src/routes/plans/+page.svelte
+++ b/src/routes/plans/+page.svelte
@@ -495,12 +495,12 @@
       planTags = [...importedPlanTags.existingTags, ...newTags];
 
       // remove the `+00:00` timezone before parsing
-      const startTime = `${convertDoyToYmd(planJSON.start_time.replace(/\+00:00/, ''))}Z`;
+      const startTime = `${convertDoyToYmd(planJSON.start_time.replace(/\+00:00/, ''))}`;
       await startTimeField.validateAndSet(getDoyTime(new Date(startTime), true));
 
       if (isDeprecatedPlanTransfer(planJSON)) {
         await endTimeField.validateAndSet(
-          getDoyTime(new Date(`${convertDoyToYmd(planJSON.end_time.replace(/\+00:00/, ''))}Z`), true),
+          getDoyTime(new Date(`${convertDoyToYmd(planJSON.end_time.replace(/\+00:00/, ''))}`), true),
         );
       } else {
         const { duration } = planJSON;
diff --git a/src/utilities/time.test.ts b/src/utilities/time.test.ts
index bec63c07f3..70e0c45bc5 100644
--- a/src/utilities/time.test.ts
+++ b/src/utilities/time.test.ts
@@ -202,6 +202,7 @@ test('convertDoyToYmd', () => {
   expect(convertDoyToYmd('2023-001T00:00:00', false)).toEqual('2023-01-01T00:00:00Z');
   expect(convertDoyToYmd('2023-032T00:00:00', false)).toEqual('2023-02-01T00:00:00Z');
   expect(convertDoyToYmd('2023-048T10:32:44.123', true)).toEqual('2023-02-17T10:32:44.123Z');
+  expect(convertDoyToYmd('2023-04-10T10:32:44.123', true)).toEqual('2023-04-10T10:32:44.123Z');
 });
 
 test('getDaysInMonth', () => {
diff --git a/src/utilities/time.ts b/src/utilities/time.ts
index d40b073224..2d1c3ab2d9 100644
--- a/src/utilities/time.ts
+++ b/src/utilities/time.ts
@@ -383,7 +383,7 @@ export function convertDoyToYmd(doyString: string, includeMsecs = true): string
       return `${ymdString.replace(/(\.\d+)/, '')}Z`;
     } else {
       // doyString is already in ymd format
-      return doyString;
+      return `${doyString}Z`;
     }
   }