it may just be for people on the android app? it's not showing it marked as mature for me and I'm on browser, and apparently the automated moderation for the app has been flagging lots of things that don't actually need it recently. the post itself may have a notice saying it's had a content label applied which should have an "appeal" button on it, but if you aren't seeing that then I believe you may be able to send in a support ticket about it saying that the flagged post isn't mature. but it may or not not take a while; I think they're getting a lot of those.
I'm not seeing an appeal button and have gotten no notice, so I'll follow your advice and send in a support ticket. We'll see how it goes, I've had someone tell me it wasn't flagged on their end, so maybe it was just a glitch? Idk, hopefully everything can be resolved because people NEED to see The Skizz. Thank you so much for your help!!