Thank you very much Luisa_Emme for your reply on this topic.
I’ve had quite a hard time trying to figure out what was wrong with my config file, since I couldn’t get any records to be sinked to the corresponding collection. It turns out that I was debugging the wrong file – the “problem” was in the WriteModelStrategy class, in this case, UpdateOneTimestampsStrategy.

Although it makes total sense to leave the “_id” field in the document and, thus, in the “value.projection.list” (because some strategies depend on it for insertion/updating), I really think a proper documentation is lacking in this case, especially when such value comes from the Record key.

In any case, thanks again!