There is a custom that many have to not eat by other peoples houses on Pesach. Seemingly it's even if they have the same chumras or perhaps even more chumras (what I've learned over time is not necessarily does someone have "more" chumras, could just be different chumras.)
My question is is such a custom mentioned or brought down any where in Seforim? Is this a relatively "new" custom? How old si it? I suppose it's a relatively "new" thing since perhaps eating by other peoples homes in general might be a new thing.