According to this story, that's the case. Some people are so lost in their own delusion that they will attribute any action to some secret agenda. Of course, I don't think we should all walk on eggshells because of people like this, but in this case, I think it's fair.
Maybe after this, Maureen will realize she isolated herself. Did she really think this was the best way to feel invited to a group? I think it is one of those strange cases of negative self-importance. The person feels relevant, like everyone is paying attention to them, but in a negative way, like thinking everyone is thinking about them. The truth is, most people don't even notice us, and that goes for most people. It's bittersweet to know we're not that important, but it's nonetheless freeing.
This act of malicious compliance, or how I like to call it, 'petty decency', might push Maureen to the brink of her own delusion, but I think it is for a good cause. Everyone at the office, and hopefully even she, will realize how ridiculous it is to organise breaks like that.
The other, more mature option would be to directly address this issue with Maureen. Maybe all she needs is to feel seen and to realize she is making a fuss over imagined scenarios, but her coworkers chose a funnier path; let's see where it gets them.
I believe paranoid folks like this deeply wish to be included, but it would take a bunch of positive leadership qualities to actually achieve that, and I assume her coworkers just want to have fun and keep not caring about her.
Do you think this problem will get bigger and bigger, or will Maureen finally come to terms with the truth that nobody cares that much?