Should I report memory leaks in casino game forums or contact support directly?

It’s a memory leak -- some kind of programming error that causes the game to crash. Don’t post here on the forums; people here just want to play your game. You should send this information to support@whatever.com, who will then pass it along to the developers. Better yet, shoot a quick screen capture video of the problem and include steps to reproduce it. The programmers will be grateful, maybe even award you with a “Bug Hunter” badge, and certainly improve the game in subsequent patches.

If you find a memory leak, report it directly to the casino. Online forums are for conversation, not for security vulnerabilities. Send an email to their support email address with detailed information, and perhaps a screenshot. They will fix the problem without disclosing the details on a public board. Some casinos have a "Report a Bug" link. If you don't see that, then check the help pages or FAQ; often they explain where to send reports of security problems.