AIBU to not understand why I am facing disciplinary at work for such a non-issue?

I think that you should join a union, OP, or get a rep involved if you are already in a union. If the workplace can make reasonable adjustments they must do so.

But - if you take them on over this, stay focused. Don't dilute your case by complaining about individuals - even a few of them - or cultural differences. Hope you get somewhere.

Regardless of the nuance and whether or not it was unreasonable of you to complain to your coworker, I absolutely do not think you should received any disciplinary action for voicing your opinion at work. That’s madness.

Freedom of speech doesnt mean you can say what you want without repercussions.

Maybe she’s on lighter duties because, as you said yourself, she has previously excelled and proven herself valuable enough to be assigned where management thinks she’ll be best placed to meet their objectives.

Picture this the other way around: you have a disability which means you cannot do physically heavy work, so your manager agrees to give you light duties as a reasonable adjustment. Understandably, you want to keep your disability private.

A colleague decides to start bitching to other colleagues behind your back about the fact that they perceive their workload to be heavier than yours. They don’t raise their concerns to a manager in the correct manner, nor do they speak directly to you.

How would you feel if you were Annie?

It sounds like your managers are being proactive in stamping out workplace bullying and for that I applaud them.

So she mentioned individuals then.

People that can meet the metrics when they're in the monitored roles progress to tasks that need less supervision.

Argue your own case but not by targeting Annie.

It seems a very strange place to work. You’re all paid the same wages?! Sounds like a communist company. Anyhoo, something will happen to change things.

Her health is no. Of your business. You sound awful.

Tommy has freedom if speech to tell you what he thinks as much as you have freedom to gossip

you brought up a grievance in an inappropriate way you should have gone via the union

their are many reasons a person cant do heavy work not just pregnancy

Annie may have conditions that are not visible to you. Let’s say she has fibromyalgia or lupus or anything that restricts her from heavy lifting. Tommy shouldn’t have gotten all shouty at you, but to keep talking about Annie in that way could be seen by management as contributing to a hostile work environment. They are trying to cover their own butts because the last thing the want is litigation.

Her light duties are none of your business

He should never have raised his voice at you but you have no idea why certain people may be put on lighter duties. If you have an issue, you should be taking it directly to management, especially if you feel you’re taking on more than your fair share.

It’s none of your business why Annie does different work to you.

If you can’t cope with your workload you either raise it with management or leave for a different job.

I haven't accused her of doing that or of being racist. I agree with you that she hasn't singled this woman out at work - she was complaining about a number of people.

But here she is going on about her and her husband being Polish and that is what I'd advise her not to do during the investigation. Suggesting that someone should behave differently because they are from another culture could be seen as singling them out, if that's what she does during the investigation.

This is your mistake: you have moved the focus from yourself being exhausted with the same repetitive task, to Annie and her tasks.
You should have gone to management and ask when are you going to have other tasks allocated, as these are overtiring you.
Now, Annie may have health issues and her RA in the company limits her to certain tasks. None of your business.
You should have kept it all about yourself. Your colleagues are not your friends. And you have learnt the hard way.
In your meetings, just focus on your tasks and that they are making you feel burnt out.

And what about the fact she wasn't singling out that one person?

who leaked it to Tommy ? @Scarlett9004 but personally with other collegues everyone is their own plan with management

Ensure you make a complaint against Tommy.

Sounds like you aren’t going to get anywhere in that company so I would look for a new job.

the fact that you’re being investigated and still didn’t click that singling her out for being polish when you were tying this absolute tripe out says you’re the arsehole.

I was questioning why the husband was at the place of work...thats not normal. Freedom of speech doesnt mean shouting at someone.

Glad to know you are perfect and never gossiped about anyone...good for you.

Good grief! The op mentioned ‘annie’ along with other colleagues when discussing the unfairness of some colleagues seemingly having a more cushy job than others. If you think that constitutes ‘abuse’ then you’re clearly not very resilient. It was a private conversation that she’s entitled to have which her colleague then went spreading round the workplace.

Article 10 of the Human Rights Act allows for ‘freedom of expression’ which in effect is freedom of speech.
Everyone has the right to freedom of expression. This right shall include freedom to hold opinions and to receive and impart information and ideas without interference by public authority and regardless of frontiers