Offline Saves disappear when switching proton off

What went wrong?: My offline save game has disappeared when I switched from Proton Experimental to Native Linux.
What did you expect?: My offline save games to be compatible between proton and non-proton states of the game.

Game Version: 1.00d
O/S: Linux Mint (21.3 Cinnamon)
Kernel: 5.15.0-97-generic

Update: Reverting back to Proton Experimental returns the save.
I believe this should still be looked into if possible (may be a steam related issue and not Last Epoch related)