Stackable Blocks not showing in block editor

Hi all,

I don’t see the Stackable blocks in my Gutenberg editor any more.
Was about to edit a page and noticed that only the v2 blocks are there.
Played with the options but when deselecting all v2 >> v3 migration options at the end of the Stackable settings page none of the blocks was shown any more.

What do I need to do to make v3 work again?
WP 6.6.1
Stackable 3.13.5

I played in a staging environment and did not find any solution.
Creating a new blank page is also not showing them.

Uninstalling other block plug-ins did not help as well.
Changing the theme – nothing.
Try to delete DB setting entries for Stackable – nothing.

Thanks for support,
Michael