Xbox controllers don't conect if steam is already running

**Game information**

All. I think its a general steam issue

**Distribution name and version where applicable**

Ubuntu 19.10

**Flatpak info**

Flatpak 1.4.3
nvidia-435-21
default
host

**Problem description**

If steam is started, before the xbox controllers are connected, they will never work in big picture mode. Instead one has to turn off steam, turn on all controllers, and then turn on steam again. Hoping that no controller will ever disconnect. If any one does, one hast to repeat the process, as re-connection doesn't work. My guess is, it has something to do with the Sandboxing, but I don't know.

**Does this issue reproduce with native Steam**

Edit. Got native steam to work. There the issue isn't present.