How would you handle what happened at the work Christmas do?

Don't feel guilty. You didn't ply her with drink or bring up the subject. She's made you upset all weekend and could have made your work life really awkward -and she's at a management level and should know much better. She obviously doesn't feel guilty about her behaviour or she would have apologised (if she actually remembers!!!).

I would escalate formally. It might teach this 'manager' to handle their drink a bit better, especially at a works do!

I think your manager is probably right about this.

If she had only spoken directly to you about it then that would be upsetting and I'd speak to her directly or let it go but as soon as she mentioned it to literally anyone else she crossed a line and at that point it's a formal complaint. I'm glad from your update you've spoken to your line manager who is rightly horrified and you are not a grass, if this manager thought it was OK to discuss your mistake repeatedly with others what else would they divulge?

What she done was immature, unprofessional & should be holding a managerial position!
She's breached confidentiality!

YANBU - make a formal complaint

She will know that she made a fool of herself by going on and on to people who weren't interested. The other people present will regard her as a joke.

You had to apologise for an error you made. She has to at least admit that she made an error.

Well she shouldn’t have given you a reason to ‘grass’ then 🤷‍♀️.

Complain away!

This manager has been so out of line. I’d not want to make the situation larger by making a formal complaint, but I would def mention it to my own line manager in a 121. If a fellow manager did this to someone in my team I’d want to know, and I’d be mortified and angry with that manager, never the team member. Think of it like health and safety too - this likely won’t be the only/last time that manager is so unprofessional, and that’s hugely harmful to other colleagues and the business. You can flag it informally and hope the manager gets the nudge they need to get their act together. How dare they! Lucky for them you’re a reasonable person, I’ve worked with people that would go ballistic over this. Good luck!

This is very unprofessional of person, hopefully your LM will treat this with the respect it deserves.

If you raise this as an issue the narrative around your mistake is still going to continue.

I would ask to speak to her individually and just say you didn’t appreciate her raising it at the Christmas do as it was inappropriate and you also really didn’t appreciate hearing about it third hand from other colleagues who shouldn’t be involved. If she has a problem in future she can raise it with you directly in the office.

I'd escalate this to her manager after asking her if she remembers what happened and giving her time to apologise. What she has done, getting drunk, dragging up a 6 months old mistake, badmouthing you to colleagues, is far worse than accidentally sending an email to the wrong person (who hasn't done that?).

I'd bring it up.
This person is in a managerial position and shouldn't be discussing anything to do with your work performance at a work Christmas party -certainly not with other staff members. Totally inappropriate and unprofessional.
This thread is proof that getting absolutely smashed at a works social is a very bad idea (seeing as there was a long thread about it the other day!) .

this.
You are certainly justified if you wanted to take it further. Whether that's actually the best thing to do will depend on your specific organisation set up, how she's viewed, how you are, how hot they are on workplace bullying, how frequently you will have to work with her in the future, etc. All of which only you know.

"It was at a party/she was drunk" are not reasonable excuses. Either the work Christmas party is regarded as an extension of the workplace, in which case you still have to maintain appropriate behaviour (whilst enjoying yourself) OR it is entirely separate from work, in which case it is completely inappropriate to talk about specific issues in detail (and could border on breaching data protection guidance if in a public place) and berate someone for making a comparatively minor mistake.

You could try speaking to her first - it could be that the reason she hasn't come to you is because she genuinely doesn't remember it, or in her mind she mentioned it to you once in what she thought was a jokey way and doesn't realise she kept repeating it and did so aggressively.

I know you don’t want an apology, while seems a reasonable stance, but I wonder if what you like is an acknowledgement that this behaviour shouldn’t have happened?

Sending an email to the wrong person is hardly worth talking about 6 months later or go on about how much time it took her to fix or even doing training to ensure it doesnt happen again, madness if you ask me!

However, some manager who isnt even your line manager getting drunk and then approaching you like this is completely batshit crazy on her part and then to further bad mouth you to others is not on!!

Send an email to HR, and I'd be petty enough to ensure the batshit manager knows I'd sent it to the correct HR email address too!!

Good advice from @Hazeby - figure out what you want. I would want the matter to be closed and move on - but it’s up to you.

This kind of decision depends on the outcome you want. Do you want a simple apology? Do you want her formally reprimanded? Do you need to have a good working relationship with her going forward?

I would frame it as a check-in with your line manager that this has happened, you’ve done the training, learnt from your mistake and have now had this experience. It has now questioned whether you are able to move on from this especially as colleague shared it with other team members. And if there is an on going issue that you would prefer that the matter is dealt with in the workplace rather than like this. If the matter has now been resolved then you would prefer this was not shared with other team members in this way.

As she hasn’t apologised you have to follow this up.

I work in, what sounds like a similar environment, and your error isn't unusual and won't be the only time it's happened. We are all human and these things happen.

She was very out of order discussing this with you at the party, and even more so with other colleagues.

I'd discuss this with your manager and ask that it's taken seriously and ask for it to be documented and also request another meeting to discuss what action has been taken. If they try to brush it off/under the carpet I'd take it to HR.

YANBU to be upset, but no good will come out of a formal complaint.

Everyone will consider HER the trouble maker and unprofessional for HER drunken behaviour. Be the bigger person. All drunken talk is nonsense, she is not management material.

She ll be in the horrors now, keep the head down and pretend nothing happened.