This issue was brought up in this post but no one responded.
I am running into the same issue. Webflow says that any deleted assets will return to the manager if they are used on the website. Trusting this to be the case, I deleted all assets in the manager as over the course of the site build we’ve ended up with a lot of unused versions of various assets. Now I’m finding that not all assets were returned to the manager.
This is causing issues with alt text and I have no way to add alt text across all instances of an asset anymore, but can only manually add them on each individual instance (not great). I don’t think I’m worried about the assets totally breaking upon site launch as this post talks about, but maybe there is something I’m not aware of.
To me this seems like a webflow bug and should be made known!
Will provide read-only link if you need it.