These things I've noticed I wasn't sure if they are bugs or intended features.
1) Legion have a demolish ability (+50% vs cities/fortified units, -50% vs units). I noticed when my super legion were dying to warriors
2) I sometimes have furs that show 2 culture icons on them (I'm only aware of 1 possible through the temple).
3) Harbors and Seaports provide a static production bonus AND a bonus to sea resources (sea resources is undocumented in the building popup if its intended).
1) Legion have a demolish ability (+50% vs cities/fortified units, -50% vs units). I noticed when my super legion were dying to warriors

2) I sometimes have furs that show 2 culture icons on them (I'm only aware of 1 possible through the temple).
3) Harbors and Seaports provide a static production bonus AND a bonus to sea resources (sea resources is undocumented in the building popup if its intended).