Homematic Blind Actor HMIP-BBL: blind not opened to 100%

I’m using Home Assistant to control a whole bunch of homematic devices. Everything works fine except the control of the blinds actor HMIP-BBL. When executing cover.open_cover the blind will go up until 100%. But it won’t stop at 100%. When reaching 100% the blind motor direction will be reversed and the blind will go down to 96%.
I also tried with the command cover.set_cover_position but got the same result.

Any proposals how to fix this?

By the way: if I execute cover_open directly from the homematic UI everything works fine.

did you find a way?