add & remove rather than update when session id changed

src/matrix/calls/group/GroupCall.ts

@@ -233,10 +233,17 @@ export class GroupCall extends EventEmitter<{change: never}> {
                         }
                     } else {
                         let member = this._members.get(memberKey);
-                        if (member) {
+                        const sessionIdChanged = member && member.sessionId !== device.session_id;
+                        if (member && !sessionIdChanged) {
                             log.set("update", true);
-                            member!.updateCallInfo(device, log);
+                            member.updateCallInfo(device, log);
                         } else {
+                            if (member && sessionIdChanged) {
+                                log.set("removedSessionId", member.sessionId);
+                                member.disconnect(false);
+                                this._members.remove(memberKey);
+                                member = undefined;                                
+                            }
                             const logItem = this.logItem.child({l: "member", id: memberKey});
                             log.set("add", true);
                             log.refDetached(logItem);

src/matrix/calls/group/Member.ts

@@ -132,29 +132,7 @@ export class Member {
     /** @internal */
     updateCallInfo(callDeviceMembership: CallDeviceMembership, log: ILogItem) {
         log.wrap({l: "updateing device membership", deviceId: this.deviceId}, log => {
-            // session id is changing, disconnect so we start with a new slate for the new session
-            const oldSessionId = this.sessionId;
             this.callDeviceMembership = callDeviceMembership;
-            if (oldSessionId !== this.sessionId) {
-                log.wrap({
-                    l: "member event changes session id",
-                    oldSessionId,
-                    newSessionId: this.sessionId
-                }, log => {
-                    // prevent localMedia from being stopped
-                    // as connect won't be called again when reconnecting
-                    // to the new session
-                    const localMedia = this.localMedia!;
-                    this.localMedia = undefined;
-                    // don't send a hangup event, as the old session id client is offline already
-                    // and we'd send it with the wrong session id anyway as callDeviceMembership
-                    // has already been replaced.
-                    this.disconnect(false);
-                    // connect again, as the other side might be waiting for our invite
-                    // after refreshing
-                    this.connect(localMedia, this.localMuteSettings!);
-                });
-            }
         });
     }