On startup of a client it shows a message to update to a newer version even though both server and the client are the same build 8.5 2021-11-02 (build 85420021).

If I click "update now" then it says file download failed.
I can see a new file on the client windowsnet.85420172.ha.tmp of zero size. I suspect client tries to update to the build 85420172.
Why is that?
How to get rid of that?