Just notice some strangeness...

Indo Iranian Light cavalry is --> Heavy Cavalry... descr say they are light, but their class is heavy, what that means for?
Taxillan Agema, description say it was cataphract without horse armor, --> was light cavalry...
Katuvarram --> Lusotann bogyguards is the only BG unit with "Light Cavalry" class... why?

Just curious, what did the Heavy cavalry and light cavalry attributes do...