Heyo,
I'm facing a weird thing here. If I have a block created in the assets panel, drag and drop it to a content area then delete it from the assets panel and clean the trash, the content area will have a block without any id or content link that won't be shown. This means that the editors are not able to see and remove it. The only way to remove it is to alter the content area (add or delete a new block).
I tried to create a fresh alloy solution and reproduce the issue but if i delete the block from the assets panel, it is not visible in the trash bin. Also, it is still visible in the content area but uneditable. That's a good thing since the editors are able to remove it.
I manage to reproduce the issue in two different solutions, both of them using older versions of CMS (11.8 and 11.10.1) and having a working trash bin. Is this a known issue? I found another topic started in 2013 with the very same problem but no solution posted there. Was anybody able to fix this?