when interacting with villagers for the first time they interact normally by opening the trade menu, but as the game advances the trade menu becomes buggy by refusing to open usually after leveling up the villager to expert or above, the trade menu closes as soon as the player clicks on the villager making it impossible to trade with said villager. villagers also refuse to perform tasks based on jobs such as farmers not farming. villagers also wont breed and get full inventory of food and freeze on one block unless hit or moved(hearts have only appeared once with each set but nothing happens afterwards) . this has affected all professions of villagers on vanilla server  and has killed off many villages due to the wide spread problem