I think the problem was due to the size of the dataset, which ended up reaching my limit and thus caused this problem. When I retry it, I'll do so in smaller batches. In any case, I have now reached out to the portuguese forum community to ask for approval with this. Thus far, I've gotten no reply, however.

I've already stopped. I'm currently just reverting my edits. Why would we not be able to use opendata though?

Eu já me apercebi. Acho que a solução é mesmo partir em tranches. Peço desculpa...

This is open data. I thought I added the source (https://opendata-sig-cmvalongo.hub.arcgis.com/). That being said, I'm having some troubles, since, with such a large dataset, it's uploading the nodes as pins before uploading the actual polygon. I didn't discuss this with anyone, because I didn't think it would be an issue. What is the right procedure here?

They are intentional. I made a mistake when uploading my last batch of buildings and accidentally added all the nodes as points as well, so I'm reverting it all so I can re-add them without the separate points.