I have a guess, but I’m not a web developer. Are you? If so you can probably even patch your system:
This file is sitting in your C:\Program Files\Duplicati 2\webroot\ngax\index.html if you want to test edits.
If you’ve been doing autoupdates, this folder is just a launcher though, so current update is elsewhere.
I don’t know history or code, but maybe the precise message is precisely wrong for one of the cases…
If that is the case, maybe it should just talk about Stopping instead of stating more than it really knows.
I didn’t find any Issue opened on this for development, but I might have missed it. Regardless, if this is proven by you to be easily fixable at least to avoid confusion, then maybe an issue could be filed for a permanent fix. Anything needing deep code investigation is not likely to happen. Too few developers…
Duplicati only exists and improves thanks to volunteers for code, test, docs, forum, and anywhere else.
If anybody could dig further, the GUI code is probably below, and also explains the delay in either case: