Why am I notified when a topic I am not involved in is marked as solved?

On several occasions I have received a notification that a topic has been solved even though it was not my comment which was marked as a solution. I mostly ignored this as I assumed that this was normal given that I was actively participating in these topics so it makes sense to notify my that the topic has been solved. However, Today I received a notification that a topic I was not involved in, and had not even read yet, had been solved by a user which I do not follow. I believe this issue may be connected in some technical way to the scenario I described above as well, though I can not say for certain. I would be curious to know if anybody here can say what is causing this issue, and if this is a Privacy Guides forum specific issue, or it is a more general discourse forums issue.