Yes, it is: you need to peek the gloryhole during wednesday's night with 5 sanity.
I don't know if answers for this question could be useful, but let's try: Have you unlocked Northcrest and the acces to the munbury complex? What is your relationship with Logan and Ste? Have you compleed country road storyline and if so, good or bad ending? At night (around 20-24) can you talk to Ste about the hole in the fence? What is your mouth experience?
If you want you can save your game on page 12 or more and upload it on filebin.net so I can try to see what is wrong (if you're playing on windows).
BTW I suggest you to reply a new post that has the same problem for three reasons: other could have the answer, others could have the same question and the replies don't get buried (for example I read that you'd try to change role or position but only by chance I read your comment about still not be able to trigger it.
Okay, I have unlocked munbary complex(all four directions), have both 2 hearts with Logan and Ste, helped everyone during the country road event, had seen the gloryhole with Ste before Logan fixed it(and the dialogue after it is fixed), and my mouth experience is beginner.
And I would appreciate help for this so I have uploaded here https://filebin.net/nh02690gh71vicmf
But do take your time, since this is like to fulfill my pure curiosity.
I have no idea why it doesn't happen: the minotaur shows up but the game over scene no. This is my save https://filebin.net/5x4hx8u550h0fyl6
I've tried to see if lowering your stats does anything and nothing happened. If you find how to unlock this scene in your save let me know!