Tested without any other addons, can replicate all the time, see below:
Any chance for a fix? Is this some kind of limitation? It's very annoying :(
If a fix is not possible - can we at least get a toggle to disable moving of map?
Being forced to top-center position is kind of annoying for sure

Step 1: Open Map & Quest log frame, and relocate it where you like

Step 2: Open full-screen world map

Step 3: Re-open Map & Quest log frame, it will now be at center-top position again

I get this too. Very frustrating. I hadn't spotted that it was in response to opening the world map. Thanks for highlighting that!

Any comment or reason for no fix?
It would be appreciated as people are taking the time to report things...
Thanks

I ended up disabling the addon for now as I like to have a bug-free UI.
Will re-enable when this is looked after. Two and a half months since this was posted with 0 response from addon dev, so perhaps they are not playing the game right now? Too bad :(