Automatic upgrade to 10.4.20 not working

Dear Community,

I have been running 10.4 for quite some time and did automatic upgrades to all minor versions so far. 10.4.19 went smoothly a few days ago, but as you can see the upgrade button is missing for 10.4.20 (I can only use re-check). Is it just me, or do others experience the same?

The status report is all green (except for the latest upgrade, of course), all upgrade wizards performed, DB structure is fine, …

Best regards,