the villagers dont want to open the next trade space

I was trading with some villagers in my new game, and I wanted to unlock the next trade so I maxed out one of the trade on the villager until it was disabled then I clicked out of the interface and still five minutes later he wasn't opening up a new slot and he still had at least another 3 trades to go so I tried another villager same problem. now I'm not sure if this is only my game or the fact that its new but its really annoying can you please fix it.