4 Y/O saying teachers are mean

This is the 2nd year my son is in preschool. He has some speech problems so he had to do two rounds of pre k. Well lately he's been fighting us about going to class. Saying how he doesn't want to go, he hates it, and his teachers are mean. We have asked him how they are mean and this morning he finally told us that they laugh at him. Specifically that he fell and they laughed. So I asked him if he was being a goofball when he did fall and he said no he slipped. We told him how it's not ok to be lying about this stuff so if he is fibbing he needs to stop. But he tells us he's not. I do find it very odd because he has the same teacher he had last year however he has a new assistant teacher and a new speech therapist. But he didn't start saying this until the new assistant teacher came in last week. Before then and all last year he has always loved going to class. He only complains about it though on the morning before we go to leave. Once I pick him up from class he always seems happy and tells me he had a good day. So idk if I should bring it up to his teacher, or just give it some time to see if it changes??

Ok so drop off this morning was super hard. So I went ahead and told the teachers the concerns and the other teachers were there to hear it as well. And they all couldn't recall him falling. I told the teacher that I'm aware he could just be talking silly. The assistant teacher did say yesterday he got upset because he wanted a certain toy someone else was already playing with so she set a timer for them to take turns. But that's all she could think of. Which my child definitely does have a sharing issue so that's completely understandable. But what irks me is the teacher showed no concern. They basically all just turned their backs and started to ignore the fact that my son was not letting go of me and freaking out over me leaving him. Usually when a child is having a hard time they take them and distract them so the parent can leave. Nope not me. I was about to be in tears because of how my son was being but I was finally able to sign him in and walk out which then the assistant teacher grabbed him and held on to him so I could get out the door.

Talking to my husband about this he feels there is more going on. Because of the fact that our child typically never lies about someone laughing at him. I mean my husband will laugh at him and he comes running to me to tell on dad. And the fact it just started out of the blue when he has always loved class. So idk... I'm gonna try and talk to the teacher again at pick up and see what else is going on. And hopefully next week will be better.