They aren't full, when I looked at their information they were at like 112 out of however many. (?)

At first I thought it might be due to the whole "1 house per account" thing, because I have that other character (on that other server on that other data center) in a FC which does have a house,
AND, that character also has a shared estate with someone else... but I own neither and this is again... a character on a different server.

What I had read as far as that is concerned is 1 house per account *per server*, and that it shouldn't affect joining a FC on an alt that's on a completely different server.

Could that player that invited me possibly "rescind" the invitation, even though I still had the countdown timer showing on my screen? Is it even possible to rescind an invitation? (I've invited players into my FC, never noticed an option to withdraw it tho).