RxJS on complete callback not executed with mergeMap

[Mr-OldWang]

I used angular interceptor to intercept http request just like this below, the complete callback not executed with mergeMap:
return this.ac.getToken().pipe( take(1), mergeMap(() => next.handle(this.authHeader(req)))
I searched the solution and said use take(1) to let it know the request is complete . It works on angular 15.1.X .
But when I upgrade to angular 15.2.8 ,the complete callback cannot be executed again, I wanna ask what the reason is related to angular version as it is rxjs issue.
Is there any solution about this.