What is AIErr 1413960793 (YTGT)?

I'm getting error YTGT when I try to tag text art objects during either a selectionChanged callback or documentChanged callback using the AI 2021 SDK.

art is an AIArtHanele and c is a char*

AIErr err = sAITag->SetTag( art, "objTag", "", &c );

Any ideas what the error means and how to avoid it?

UPDATE: the third argument needs to be the literal "string" which gets around the error, although the function works as expected either way. What's more concerning is that even with no error here, calling this a few times later leads to Illustrator crashing in another thread when path art, which was not tagged, is simply scaled. It turns out it just doesn't want to be called during a callback. Push context and pop context doesn't help. 😞

When it's manually called, all is OK. It's far less useful, but I guess something is better than nothing.