I did these steps:
- Place Lectern and let villager take a profession (when offer is good then point 2)
- Trade with villager one or two times
- Change villager into a zombie villager
- Cure zombie villager
Villager sometimes had old offer with discounts, but sometimes he had different offer than before (with discounts too). This bug doesn't appear when I destroy Lectern straight after point 2 - he always had an old offer (I checked it 9 times).
I notice that sometimes when villager changes from a zombie villager to villager for a moment he is without profession. I share video with that moment below.
Sorry for my English.