I think you found a bug. I posted it as https://core.trac.ww.wp.xz.cn/ticket/50912#ticket
We confirmed that it’s a change in behavior from 5.4.2 (Thanks, Brett!)
Moderator
Jonathan Desrosiers
(@desrosj)
Principal Software Engineer & WordPress Core Committer
Copying my response over from the Trac ticket in case someone else stumbles on this topic:
WP_AUTO_UPDATE_CORE is used to configure the types of WordPress updates that you’d like to receive automatically. In your case, you were specifying minor updates (updates to the Z number in X.Y.Z).
This is actually the default behavior of WordPress Core. So you can safely remove that constant and should not see any problems or changes in behavior.
However, sometimes it is desired to define WP_AUTO_UPDATE_CORE as minor, so the issue described here will need to be fixed.
The plan is that this will be fixed when 5.5.1 comes out for anyone that wishes to continue defining WP_AUTO_UPDATE_CORE with a value of minor. For that, please follow along with the ticket mentioned above. Thanks!
I’ve been having the same issue.
Thanks for linking to that ticket!