Have any one experienced withdrawal/deposit being stopped by exchanges, just because the amount is getting moved to a gambling site. Recently I made withdrawal from a gambling site to an exchange. After that as I wasn't able to participate in one of the IEO launch I withdrew it back to the gambling site. For days it didn't get transacted. The first transaction automatically got cancelled. The second one was under process, but there is no details about it. Later through the support team came to know about the issue and then I moved the fund to another exchange and from there I deposited back to the gambling site.
This can happen. Every exchange has it's own blacklist and as i know (Kuna io for example) they can cancel some withdrawals to services they consider as being not trustworthy.
Please, tell us about exchange from what you tried to withdraw and a gambling site where you send your money. For some people it can be useful i think.