I marked my game as mature, and I started seeing NSFW, I untagged it as mature, 

I STILL SEE IT 

HELP

Right, I think there's a bug. Contact support and let them know. But first double-check your account settings, the checkbox was toggled automatically and you might be able to set it back.

Edit: never mind, your latest game is still set as NSFW, so you'll keep seeing NSFW projects until you turn that off.