Somebody know if allocating inventory to a Sales Order (meaning the committed quantity changes) triggers any event in the Sales Order record?

I do not believe so

No it does not trigger anything

If you have not already, confirm the behavior on records by checking the scripted records page and see what could be firing on the records in question. Also potentially look at workflows if you are seeing something you don't understand / can't explain. You'll be the local hero if you document everything, and despite people claiming that they don't need that you'll discover quickly it is very popular.