Buttons missing in compiled app

Hi,
working on a little app and it works and displays fine in the companion, but when I install the .apk, several buttons have vanished from the screen.
What am I missing?

We do not know.

Provide either relevant blocks or an aia project.

There are no relevant blocks.
The buttons missing are still "dummy" and not used in any blocks.

Update:

After exporting it to .aia and reimporting the .aia as a new project, the missing buttons are displayed now.
That's weird...no changes to the blocks or design were made, just exporting and reimporting.
The exportet app still doesn't show the buttons when installed, the re-importet does.