Villager changed profession after being traded with.

So, I needed an auto carrot farm to make large amounts of golden carrots. I decided to use villagers because they would be the simplest option. I placed down a composter, and the villager became a farmer, as expected. I traded with him so he wouldn't loose his profession, and broke the composter because I couldn't keep it there. I had a second fillager in the farm as well, and he needed to be a fletcher. So I placed down a fletching table. out of the corner of my eye, the first villager lost his profession (after being traded with) and become a fletcher. I look inside of his UI and he is still leveled up like he has been traded with. I tried to revert the change by replacing the composter and breaking the fletching table, but the villager will not change back. I was looking to see if another bug like this existed, and the closest one was MCPE-117852, but that one was resolved.