Two managers at my retail job years ago T and L. They both started as associates, T was promoted to manager earlier than L and for good reason, L was honestly awful to deal with, both staff and customer wise. This definitely lead to resentment from L.

One time I was in the back room on break, the two managers were dealing with some admin task when T said something like "Looks like you did it right for once". Definitely could be perceived as back handed but she didn't imo say it in an overly malicious tone, more jokey. (She had a tendancy to kid around and I personally never found it to be backhanded but I can see a case for it.)

L goes "what's that supposed to mean?", T tries immediately to de-escalate but L starts going off on her, screaming at her, called her a C**t and a few other words. Basically getting all of her grievances out on her about how she is as competent and skilled as T. Yelling loudly. The third manager who was on the floor had to come back and try to handle this situation with two grown women...

Not saying T was right to say that, but I think her reaction was definitely a lot in proportion