Its true. This happens to me several times. At first, it was working fine and smooth. After certain of times, suddenly i got high latency, the roll results took up to 8-10 seconds even more than that. That is when i started to lose BTC especially large amount.
The site has high latency even for free rolls. Sometimes I have to refresh the page several times because the rolls get stuck and it takes several attempts to succeed. To me this is an indication that the site doesn’t have enough server capacity to meet the demands of all their users. The site is also bloated with banners and other unnecessary things that use a lot of resources.
I can’t say for sure whether your experience is a random coincidence that you are trying to rationalize or if they are actually manipulating results. If you really believe that you are being cheated, there is no reason to continue using this website.