Watch switches continuously to sleeping mode after SW update 8.21

After the 8.21 Software update my Epix continuously switche to sleeping mode. Very annoying, the watch faces goes black.

I haven’t changed my sleeping schedule, so no cause there. I suppose it’s a bug in SW version 8.21. I haven’t experienced this bug before…. 

Are there more people who have the same issue and maybe have a fix for it? I already turned the watch off/on several times….