I think that some exchanges changed their number of confirmation policy during this period of uncertainty - and while there seems to be a hardforker attack upon the bitcoin network.  Bitfinex, for example went up to 7 confirmations, but states that they plan to return to lower confirmations in the future.  I cannot remember what their previous requirement was.

Some of the exchanges may return to fewer number of required confirmations when they feel more comfortable that replay attacks are not as likely (as such replay attacks may have seemed to be more likely during the hardforking transitional period).