I was launching Skyrim SE from the Galaxy client, with a custom executable, a batch file that loads Mod Organizer 2 and runs skse64. Cloud sync of save files worked, as well as playtime. After latest update of Galaxy, it will stil load Mod Organizer 2, which then refuses to launch skse64 (see attached screenshot).

The problem lies with Gog Galaxy, because:
1. it started with its update
2. When I manually start Mod Organizer, it loads skse64 and the game itself correctly.

The content of the custom executable batch file is:
ModOrganizer.exe -p Default moshortcut://:skse64_loader

Are we talking the most recent 2.0.71.2 update, or one of the others?

2.0.71 Hotfix (24 August 2023)
That's what the changelog says.
------------------------------------------------------------

Weirdly, now it works ok. Maybe it required a system reboot? I can't recall if I tried that.