Villager problems?

Ohai, so I found two zombie villagers and cured them. However, when I finally try to chose the trade of one of them, the trade prices of the another one went back to normal, no discount. Before, this same villager showed like a consistent discounts while I was trying to find an enchant, but when I locked the enchant of the other one, the prices went back to normal (UP).

So, is there a limit of how many discounts like this you can have? I mean, only one cured zombie villager discount active?

In general the discount will last forever to my knowledge, as long as you keep trading with them consistently to resting good gossip. I think that was true a few versions ago, but perhaps they changed it, or I may be wrong