Not all conflicts around Christmas are about the obvious. The racist comment that is made without anyone standing up.
There is also a lot under the surface, I think. Such within a family, which has been felt by those involved during the year, but perhaps not said out loud. Something that tends to overflow if the atmosphere becomes too stressful and the demands too harsh.
Because it must be during Christmas and other holidays that children who have a hard time otherwise often have it harder. Things escalate and also it disappears for those safe (which could be the school) for a period.
The problems don't appear because of Christmas, but maybe they become more visible to others then.
The only thing I really want to say is: if you see or notice something that doesn't feel good - tell me. Ask, do whatever you can. It's always worth it.