YES..avoid sending any ETC (if you have it) to GDAX/ Coinbase.
It is not being credited there at this time..things appear pretty wacky the last few days as the dust settles and exchanges decide to list ETC trading pairs...Kraken announced a few hours ago they are now listing ETC

https://www.reddit.com/r/Bitcoin/comments/4ut2iz/coinbase_just_announced_that_they_are_pocketing/