Problem dragging and dropping references from Zotero

I am currently writing up my PhD thesis, and my workflow relies on being able to dragging and dropping references from Zotero. This had been working fine, but recently I had experienced a problem whereby when I tried to drop drag from Zotero and drop into Scrivener, the drop would fail, meaning that the expected reference marker – which looks something like { | Meek, 1971 | | |zu:3656938:44G9DXZR} – would not appear. When this happened the first time, restarting both programs seemed to fix it. Today, however, it is not working again and I cannot find a workaround. I work with both in full-screen mode, and I don’t know whether this is related, since previously when I took Scrivener out of fullscreen mode, I had been able to drop in the references. This workaround is currently not working however. I am assuming this is a problem with Scrivener itself, because I seem to be able to drop Zotero references into other programs.

Any help would be much appreciated!

OS X 10.14.4
Scrivener 3.1.2

What happens if you try to drag and drop text from another program into Scrivener? Does that work?
All the best,

Thanks Keith. I haven’t been able to reproduce the problem again since I posted this. I don’t know why this is. If it reappears, I will check whether it is possible to drag in text from another program.