10.15.4MacBook Pro 13" Mid 2012Apple Wireless Keyboard 2009 MC184LL/BI had the same problem.Could solve it by using 10.11.6 on a MBP 13" Mid 2009.Renamed it in system preferences / bluetooth.It was working on the MBP 09.When i reconnected it to the MBP 12 / 10.15.4 first it showed the old name, but after 5 seconds it got the new one & kept it.Looks like 10.15.4 can't write the changes on Apple Wireless Keyboard 2009 MC184LL/B.Maybe the keyboard is not getting OS support anymore, although produced until 2015.?hope, the workaround is helpful.
Eddie would go
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Last seen
User for