Thank you for the reply Jason! I am glad you could grasp my dilemma, that sounds like it could be it (I was beginning to worry I hadn't managed to express myself at all).
Thank you also for the clear steps to fix it. Although laborious, it still beats writing the metadata for each citation from scratch again.
I still have a couple of questions, if you would be so kind:
I believe I did check for duplicates and pressed the “not a duplicate” button. It seems then that the deletion of the citations in the Docs document was the crucial missing step. Does that mean that each citation in a document always stays “unique”, and wouldn't change its “default citation name” (i.e. “(Johnson 1912)”) even if I would change all the metadata in the library (including year and author)?
My first instinct is to mostly avoid making duplicates in the library from now on, just to be on the safe side, but are you saying it should work fine IF I mark the new entries as “not a duplicate” before I use them in a document?
In that case, I could continue to avoid a lot of retyping
It would, of course, be great if it were possible to avoid this problem from cropping up (or at least to avoid/skip the step of deleting and re-adding each problematic citation in the document), but since you are already aware of the problem I'm sure you're already doing your best to solve it.
Thanks again and all the best,