In the 1.16.100 update, villager cure trading was changed to be on parity with java (or close to). However, the behaviour pack files that modifies the curing behaviour in 1.16.100 was not shipped with the BDS software update. See screenshots of BDS behavior_packs folder and the vanilla behavior_packs folder for addon creators.

This results in curing a villager still giving the full maximum discount with 1 cure.

(I couldn't post this as a BDS bug because it doesn't recognise the version affected)