I figured out that in my case this was because I forgot to remove buddypress subfolder from my theme folder located in wp-content/themes/YOUR_THEME/
So I guess it was just loading some page out of it.
Anyhow, is there a general answer on how does BP technically track user’s activity, e.g. where can you see the code which tells something in BP that the user did some action?
I’m not tech guy and it’s my 2nd day with BP, so don’t blame me please.