I am having the same issue with Steam. I can see & load my Steam saves, but I cannot upload from the Switch. Keeps saying 'Upload Save Failed'. I have never used or loaded mods on any of my saves, and I have never renamed any of my save files.I am having issues uploading my save to Steam. I can see my steam saves, but just can't upload from the switch. I keep getting 'Uploading save failed.'. I don't appear to have the same issue with GoG.
Any ideas?