You forgot to request time off and you need to take responsibility for the mistake. It’s not your SM’s fault you didn’t request off so of course you’ll be written up for it and it’s always been a thing? But It’s not a fireable offense if it’s just once. Just because you do extra work, it doesn’t give you a pass to skip a shift for a party that you should have request off for.

good on you for being accountable in the replies

Idk if it’s actually a thing but at least you know this a dick move.

You didn’t request it off. No offense but that’s on you. No matter how many times you cover, stay late, come in early; none of that excuses your shifts being missed.

Not to mention that you thought your manager would give you some kind of special treatment because you “have a good relationship.” I do like that your post title is a double entendre about you being called out by your manager and everyone in the comments here about this situation