Hi,
I ran into this same problem in the new Collector App on Android after redirecting the URL for the rest interface to our new ArcGIS server machine with ArcGIS Server 10.8.1. The same mapservices are running on that new server (restored a backup of the old site to the new machine).
I have some other problems as well, not being able to upload attachments and not being able to synchronise offline maps (those problems I see on iOS as well).
I saw this workaround (somebody described it before in this thread but I didn't see a link):
https://support.esri.com/en/technical-article/000024329
but how are we to going to instruct all our field workers to do this? That is going to be a big mess.
Joris Frenkel