"Colours" panel not working correctly

Since the last update of Plasma 5.21 I notice a strange behaviour of the “Colours” panel in “System Settings”. Every example window shows the same colour for the selected background. It’s somehow annoying over time…
Screenshot_20210326_180534
Does anyone have an idea what could have caused this?

Thank you in advance :grinning:

Seem to be the new standard properties now. Noticed the same behaviour on the example pictures at

You may consider this thread solved.