Steps to reproduce
For a doc, share it with someone else. They accept the share. You delete the doc, it’s still there for them.
For a folder, share it with someone else. Drop a doc into the folder. They see the doc. Delete the doc, it disappears for them.
I’d have expected for the doc to disappear in both cases, as they’re both “shared” docs, so I’d expect behaviors to replicate. So when you share a specific doc, I’d expect that specific doc to disappear from both owners if I delete it.
The doc which I had deleted was still on the other person’s Dynalist, looking shared. They couldn’t tell that I’d deleted it. It still showed as owned by me.
I usually use the Dynalist app, and I think they’re using the website. But it doesn’t appear to be platform related as far as I can tell, as Dynalist is pretty convinced that they have the doc and I don’t.