Theme Designs only show Themes of actual Plan


under Design -> Theme Designs i suddenly only see the Themes of the actual Pro Site Level.
The last time i looked it was setup correct. So that i see all (20) Themes under the "All" Tab with the hint "Pro level only". When i activate a higer pro site level on a subdomain, i see the themes which are integrated in the plan/level.

Do you have an idea why this stopped working suddenly?