Fenix 7 Pro HR issues sleep/ GAP 20.16

Hi there,

since updating to 20.16 I have several issues with my Fenix 7 pro.

The erroneous GAP seems to already known and is not part of this post. But since the update my nightly HR is totally off. It is way too low or doesn't measure any HR reading at all. 
Usually I am around 37-42 bpm but since the update I am at 31 und 40% of the night I don't have any HR reading at all. 

(HRV is a bit lower too, but seems to be reasonable) 

Has anyone else the same i ssues/ a solution for my problem?

Thanks!