Caymen, you are in some mood today.
No, if a bus is stopped with a flat tire you don't have to stop AND stay there while they fix it. But if a bus is stopped in the middle of a lane (not off to the shoulder) on a main road, and one is coming from the other direction, it is a VERY GOOD IDEA to slow to almost a stop and be prepared to stop as you approach, and if going that slow, stopping at the last minute as the lights come on, or as you assess what is going on is not an issue.
So, maybe the bus driver didn't have his lights on in this case.
My son's elementary school has a bus loading zone and the entrance into the school runs parallel to it. The buses DO NOT put their lights on when loading and parents are ENCOURAGED to drive around the buses because it is behind the school that parents do their pickups.
Frankly, I can't understand in this situation WHY the driver would have their lights on and WHY (unless clearly marked otherwise) there would be any issue with driving by the parked/loading buses.
I think THAT is the issue here...what IS the expected traffic pattern of the school grounds when the buses are loading?
BTW, NJ has a pretty good description of their law in this area (see link below) and it seems clear to me that they (NJ) don't indicate ANY requirement that the bus lights be on when stopping (only that they go off before proceeding), and they also discuss the differences between pickup/dropoff road-side and the (un)loading in a school zone when the main school load runs parallel (and in this case motorists are allowed to pass, but at no more than 10mph).
Check the local/state laws for CT.
TJR