Save Game deleted in proton prefix when switching to other account

Game: Witcher 3 - Wild Hunt
Proton version: 7.0-4

When I switched to another user on Steam Deck and then back to my account I found out that latest save file in Witcher 3 is missing.

I did some investigation and found out, that the Proton prefix is the same for both accounts (the game was shared through family sharing, but I'm not sure if this has any impact) and the save game folder is for the same for both account as well in the mentioned Proton prefix.
When switching from one account to other, I noticed, that the save game folder is being changed. The configuration file contains id of the current user and the save game folder is being synced for that user.

My assumption here is that Steam didn't checked if the current content of the folder was synced to cloud for the first user before replacing the content of the game folder with second user.

I'm not actually sure if this is a bug in Proton or something that the Steam does with any Save Game folder.

The report names no Proton files, tests, or entry points. Start by determining whether Steam Cloud or Proton owns per-account save synchronization for Witcher 3 on Steam Deck, then reproduce switching accounts and verify whether each account's latest save remains intact.