Did you use the "Multiple accept/reject" to accept them?
I believe this is when it happens. I haven't had any issues since just accepting, or declining singularly. I do get that other members have declined my FCR, when they swear they accepted it. It also comes up that a member has declined my FCR, to find I do indeed have their FC.
I think it's just another lovable ACC glitch, that's been there for a year, or so.
"Did you use the "Multiple accept/reject" to accept them?"
Aha, thanks for the hint!
It appears that, if you tick any of the checkboxes in the column for "Multiple accept/reject", and then instead click the singular "Accept Request" or "Decline Request" buttons, the ones you ticked will all be rejected.
I'm not yet entirely sure why this is the case, but it at least proves that there is a genuine bug here. I've made a thread about it on the staff boards.
There's no place like 192.168.0.0/16.