diff --git a/lib/components/keyserver-connection-handler.js b/lib/components/keyserver-connection-handler.js
--- a/lib/components/keyserver-connection-handler.js
+++ b/lib/components/keyserver-connection-handler.js
@@ -5,15 +5,15 @@
 
 import {
   keyserverAuthActionTypes,
-  logOutActionTypes,
   keyserverAuthRawAction,
+  logOutActionTypes,
   useLogOut,
 } from '../actions/user-actions.js';
 import { useCallKeyserverEndpointContext } from '../keyserver-conn/call-keyserver-endpoint-provider.react.js';
 import { extractKeyserverIDFromID } from '../keyserver-conn/keyserver-call-utils.js';
 import {
-  CANCELLED_ERROR,
   type CallKeyserverEndpoint,
+  CANCELLED_ERROR,
 } from '../keyserver-conn/keyserver-conn-types.js';
 import { useKeyserverRecoveryLogIn } from '../keyserver-conn/recovery-utils.js';
 import { filterThreadIDsInFilterList } from '../reducers/calendar-filters-reducer.js';
@@ -27,9 +27,9 @@
 import { IdentityClientContext } from '../shared/identity-client-context.js';
 import type { BaseSocketProps } from '../socket/socket.react.js';
 import {
+  type AuthActionSource,
   logInActionSources,
   type RecoveryActionSource,
-  type AuthActionSource,
 } from '../types/account-types.js';
 import { authoritativeKeyserverID } from '../utils/authoritative-keyserver.js';
 import type { CallSingleKeyserverEndpoint } from '../utils/call-single-keyserver-endpoint.js';
@@ -38,8 +38,8 @@
 import { useDispatchActionPromise } from '../utils/redux-promise-utils.js';
 import { useSelector } from '../utils/redux-utils.js';
 import {
-  usingCommServicesAccessToken,
   relyingOnAuthoritativeKeyserver,
+  usingCommServicesAccessToken,
 } from '../utils/services-utils.js';
 import sleep from '../utils/sleep.js';
 
@@ -57,10 +57,33 @@
   const dispatchActionPromise = useDispatchActionPromise();
   const callLogOut = useLogOut();
 
+  const { olmAPI } = getConfig();
+
   const hasConnectionIssue = useSelector(
     state => !!connectionSelector(keyserverID)(state)?.connectionIssue,
   );
   const cookie = useSelector(cookieSelector(keyserverID));
+  const prevCookieRef = React.useRef(cookie);
+  const notifsSessionReassignmentPromise = React.useRef<?Promise<mixed>>(null);
+
+  React.useEffect(() => {
+    const prevCookie = prevCookieRef.current;
+    prevCookieRef.current = cookie;
+
+    if (cookie === prevCookie || !cookie || !cookie.startsWith('user=')) {
+      return;
+    }
+
+    notifsSessionReassignmentPromise.current = (async () => {
+      await notifsSessionReassignmentPromise.current;
+      await olmAPI.reassignNotificationsSession?.(
+        prevCookie,
+        cookie,
+        keyserverID,
+      );
+    })();
+  }, [cookie, keyserverID, olmAPI]);
+
   const dataLoaded = useSelector(state => state.dataLoaded);
 
   const keyserverDeviceToken = useSelector(deviceTokenSelector(keyserverID));
@@ -101,8 +124,6 @@
   invariant(identityContext, 'Identity context should be set');
   const { identityClient, getAuthMetadata } = identityContext;
 
-  const { olmAPI } = getConfig();
-
   const preRequestUserInfo = useSelector(state => state.currentUserInfo);
   const innerPerformAuth = React.useCallback(
     (
diff --git a/web/shared-worker/worker/worker-crypto.js b/web/shared-worker/worker/worker-crypto.js
--- a/web/shared-worker/worker/worker-crypto.js
+++ b/web/shared-worker/worker/worker-crypto.js
@@ -365,6 +365,10 @@
   if (!value) {
     return;
   }
+  const valueAtDestination = await localforage.getItem<mixed>(destination);
+  if (valueAtDestination) {
+    return;
+  }
   await localforage.setItem(destination, value);
   await localforage.removeItem(source);
 }