I've had two 5Xs. The first (which I think I had before 6.0.1) always charged rapidly.
I returned it for a 6P, but have since replaced it with another 5X. Now I don't know if it's 6.0.1 that's changed anything, or if it's the new phone, but this one doesn't say its charging rapidly with the supplied charger and cable, but I think it actually is charging quickly! I going to have to time it.
If I plug it into my Tronsmart car charger it always says it's charging rapidly! So the genuine charger doesn't appear to charge rapidly, and yet a third party one does?! Go figure? I'm now unsure whether I have a faulty handset, although I doubt it.