failed to save session, not sure what's wrong

[EthasTheSkunk]

more or less the title

every time I try to save a session, i get the error message saying it failed, and i'm not sure why.

some windows I can add to current session, but one or two can't.

another thing that happened would be that, for whatever reason, when restoring a session, it'll sometimes end up duplicating windows. example would be like, a session with 3 windows, it'll make 2 of each, making 6 windows, with the same tabs and everything.

any idea what I may be doing wrong?