Weird assault result

[Mowgli]

The stack has to fit into a single hex as a stack and it also needs to be able to move to the destination hex as a stack.

I'm not sure if the game calculates stacking limits before or after the defender assault losses are applied. That is: if the 50% strength loss or surrender (Fragile Morale) check is part of the loss calculation or a separate check.

If the stack would need to cross a hexside or enter terrain which one or more units in the stack can't enter, such as vehicles entering a marsh or a mixed stack of units not in travel mode and units in travel mode next to a bridge across a river, the stack will take "can't retreat" losses even though most of the stack is technically able to retreat into that hex or across the hexside.

Thanks a lot for you reply! 
So indeed I remembered that rule incorrectly. Got to be very carefull in defense! :)