Some custom taxonomies not available in Meta Value Order

I created a bunch of custom taxonomies with “WP Pods” and mysteriously some of them are not available in Meta Value Order. Actually, all custom taxonomies I create from now, are not showing up in the list. It seems that there is a limit? I am needing “stufen”.

Investigation:

• The wanted custom taxonomy are showing up for Search Form UI yes, but not for Ordering
• The wanted custom taxonomy are showing up for Ordering as “built_in_taxonomies_stufe” but not as “stufe”. And with “built_in_taxonomies_stufe” no results are loaded.
• Other custom fields like “e-mail” or “branchen” are showing up for Ordering yes, but when I duplicate i.e. “branchen” to “branchen2” it again does not showing up.
• Reset Permalinks in WP Settings done
• Rebuild Cache in S&F done
• Showing the wanted taxonomy the in Custom Post Type (the_terms() Function)
• Repair and optimize Database with WP-DBManager Plugin

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