-l Make bash act as if it had been invoked as a login shell (see INVOCATION below).
--login Equivalent to -l.
This is an excerpt from the bash manpage. So likely no, this isn't a bad thing and this is just GNOME sourcing your environment variables. You need to tell us how frequent these notification are and when they happen (also what GNOME version you're using as well as which distribution you are using). We can't help you if you don't provide that.
does emacs have an integrated terminal view inside it? Seems like maybe it's just creating a shell for you to use inside the editor or something? Either way, "bash --login" is just a login shell which I think basically just acts like if you had just logged in instead of inheriting most stuff from whatever process launched it. It in't "logging in" like some user account or something. Unlikely that it's something nefarious. At worst, it's just usual buggy linux software interacting in weird ways.