Was I wrong for asking if my kids behaved?

My boys (6,4 year olds) and I went to YMCA today they stayed at the child care place for about 20 min. When I went to pick them up my son told me that the lady got mad at him. He seemed a little worked up about it. I asked him why? And he said because he got a snack.

My boys are always so excited to get a snack when they go to that place. I never get any complaints about their behavior so I was very confused as to why she would get mad at them.

I went back and I asked nicely if they had misbehaved thinking maybe they didn't ask for the snack or maybe they were being bad so she got mad at them.

She turned red when I asked her if they had misbehaved and she said no, they were behaving and that she had just told them "come here"

I feel really bad about asking her, like I made her feel bad

But at the same time I feel like I need to have my kids back and see if someone was being unkind to them.

When we got in the car I asked again what happened and my 6yo said he thinks she was just stressed out or frustrated when she acted that way towards them

Should I have just left it alone?

Would you have said anything?