Gallery Block does not display images in grid after update to WP 6.1

Hello fellows,

I hope I hit the correct forum here.

After updating to WP 6.1, the gallery block does not render correctly in the front end anymore.

Instead of e.g. 3 columns the images are showing one per row with no margin and left-oriented, see example.

Everything looks fine in the Block Editor, only in the front end galleries are not displayed correctly.

I checked the CSS output but could not find anything suspicious.

There are no caching tools involved. Applies to galleries in old posts as well as newly created ones.

has anyone stumbled upon this and has a fix?

Thanks for looking into this,
best regards from Germany,
Rob

The page I need help with: [log in to see the link]