Yeah, but this is not an extreme case. I used MongoDB in the past when the srv protocol wasn’t implemented, same network, same DNS and I never had these types of problems.
It seems very strange that sometimes it works and sometimes not.
I’m also using FireBase for other projects and I didn’t notice nothing similar.
If you need some more logs to analyze the problem I can give it to you.
In the meanwhile I will try to host my dev environment on a dedicated server to see if I have the same issues.