[1.5 Bug] City militia only appear to defend first battle
Several bugs were introduced with 1.5 to sieges. The most consistently appearing is that city militia will only appear to defend the city for the first attack of a round - in subsequent attacks, only units stationed in the city will defend. This bug is easily reproduceable.
Another bug I encountered was the opposite: That only militia appeared to defend - the stationed army was ignored and didn't appear, resulting in the loss of the city.