Main Menu does not show up on every first start of GIMP

I'm on Manjaro KDE Plasma and right until the last update everything worked smoothly, but now when I open GIMP, the main menu doesn't show up. My GIMP window starts maximized. I usually need to move to another virtual desktop for a moment and then go back to the one that has GIMP in it and then the menu shows up! I'm able to replicate this behavior every time.

Before:

After:

Edited Jul 20, 2020 by Joe

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