Your system information

• Steam client version (build number or date): Apr 8 2020, at 20:52:25 Flatpak version
• Distribution (e.g. Ubuntu): Pop OS 18.04 Remote; Ubuntu 18.04 on Host
• Opted into Steam client beta?: Yes
• Have you checked for system updates?: Yes

Steps for reproducing this issue:

1. Both on host and remote machines install flatpak version of steam.
2. sudo apt install steam-devices on Pop OS machine.
3. Rumble works if proton game launched locally
4. Launching native games from remote have rumble (Shadow of the Tomb Raider)
5. Launching games via proton from remote to host - Xbox 360 gamepad has no rumble (Hitman 2, Kingdom Come deliverance, Shadow of War).