diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index f048fd8..172da2f 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -19,7 +19,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '18'
+          node-version-file: '.nvmrc'
           cache: 'yarn'
 
       - name: Install dependencies
diff --git a/.github/workflows/type-check.yml b/.github/workflows/type-check.yml
index 8dbde80..3f3816a 100644
--- a/.github/workflows/type-check.yml
+++ b/.github/workflows/type-check.yml
@@ -19,7 +19,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '18'
+          node-version-file: '.nvmrc'
           cache: 'yarn'
 
       - name: Install dependencies
diff --git a/src/store/actions.test.ts b/src/store/actions.test.ts
index 1a06c69..17601b9 100644
--- a/src/store/actions.test.ts
+++ b/src/store/actions.test.ts
@@ -320,7 +320,7 @@ describe('store actions', () => {
       type: ActionType.UPLOADING_WCIF,
       uploading: true,
     });
-    expect(patchWcifMock).toHaveBeenCalledWith('Comp1', { events: wcif.events });
+    expect(patchWcifMock).toHaveBeenCalledWith('Comp1', { events: wcif.events, formatVersion: wcif.formatVersion });
     expect(dispatch.mock.calls[1][0]).toEqual({
       type: ActionType.UPLOADING_WCIF,
       uploading: false,
diff --git a/src/store/reducers/_tests_/roundActivities.test.ts b/src/store/reducers/_tests_/roundActivities.test.ts
index 5249327..564aa7f 100644
--- a/src/store/reducers/_tests_/roundActivities.test.ts
+++ b/src/store/reducers/_tests_/roundActivities.test.ts
@@ -23,7 +23,23 @@ describe('roundActivities reducers', () => {
     expect(nextState.needToSave).toBe(true);
     expect(nextState.changedKeys.has('schedule')).toBe(true);
     expect(nextActivities[0]).toBe(activityOne);
-    expect(nextActivities[1]).toBe(updatedActivityTwo);
+    // The updated activity is returned as a new object (extraneous props are stripped), so use toEqual
+    expect(nextActivities[1]).not.toBe(updatedActivityTwo);
+    expect(nextActivities[1]).toEqual(updatedActivityTwo);
+  });
+
+  it('updateRoundActivities strips extraneous properties (e.g. room) from stored activities', () => {
+    const activityOne = buildActivity({ id: 1, name: 'Round 1', activityCode: '333-r1' });
+    const room = { id: 10, name: 'Room A', color: '#000', extensions: [], activities: [activityOne] };
+    // Simulate ActivityWithRoom: an activity with an extra `room` reference attached internally
+    const activityWithRoom = { ...activityOne, name: 'Round 1 Updated', room };
+    const state = buildState(buildWcif([activityOne]));
+
+    const nextState = updateRoundActivities(state, { activities: [activityWithRoom] });
+
+    const nextActivity = nextState.wcif?.schedule.venues[0].rooms[0].activities[0];
+    expect(nextActivity).not.toHaveProperty('room');
+    expect(nextActivity).toEqual(expect.objectContaining({ id: 1, name: 'Round 1 Updated' }));
   });
 
   it('updateRoundChildActivities updates child activities and keeps other assignments intact', () => {
diff --git a/src/store/reducers/roundActivities.ts b/src/store/reducers/roundActivities.ts
index 3fc011d..b3eb363 100644
--- a/src/store/reducers/roundActivities.ts
+++ b/src/store/reducers/roundActivities.ts
@@ -1,7 +1,7 @@
 import { mapIn } from '../../lib/utils';
 import type { UpdateRoundActivitiesPayload, UpdateRoundChildActivitiesPayload } from '../actions';
 import type { AppState } from '../initialState';
-import type { Assignment, Person } from '@wca/helpers';
+import type { Activity, Assignment, Person } from '@wca/helpers';
 
 /**
  * Updates the child activities of a round activity and also updates the assignments of the persons accordingly
@@ -83,7 +83,13 @@ export const updateRoundActivities = (
             ...room,
             activities: room.activities.map((activity) => {
               const updatedActivity = action.activities.find((a) => a.id === activity.id);
-              return updatedActivity || activity;
+              if (!updatedActivity) return activity;
+              // Strip extraneous properties (e.g. `room`) that may be present from internal use
+              // but are not valid WCIF schema properties
+              const { room: _room, ...wcifActivity } = updatedActivity as Activity & {
+                room?: unknown;
+              };
+              return wcifActivity as Activity;
             }),
           })),
         })),