I wrote a post, hit Post Comment and it saved as a draft. After multiple attempts it finally posted but I was unable to edit the comment even within the 15 minute window. Desktop, Explorer Windows 10. @CCadmin_Sorin
EDIT: Okay, I was posting a link to prepscholar that may not be allowed. but there was no error message or notice that the post was being reviewed.
Links to prepscholar are not allowed, so I assume at some point you edited out the link to be able to post. The pop-up is subtle, but it is there.
@skieurope Yeah I figured that out before the edit time was up. 
But initially when I hit Post Comment the comment just disappeared. If there was a pop up it was extremely subtle.
Yes, unless the post had been saved to draft, the post disappears from your view once you hit post.
It’s in the lower-left corner, disappears after a few seconds and yes, it’s very subtle, probably too subtle, particular for users who have never seen it.