I recently received a FFXIAH message, but it isn't showing up in my inbox despite the fancy "New (1)" marker on my account.
My main linked account has the (1) beside it, so it's not something that got sent to my other ones (though I checked anyway), and switching between accounts temporarily gets rid of the (1) next to my main account, but refreshing the page makes it come back anyway.
Another oddity is that each of my accounts has weird listings of the message numbers. My main one (the one with (1) appended to it) is 1-29 of 29 (despite being empty), while my others are 1-0 of 0 or 1-1 of 1.