Absence seizures??

My step daughter is eight years old and had her first seizure around a year ago. We witnessed her first seizure Dr says a prolonged absence but I’m not sold on that it lasted approx 10 min with contractions to left side real lethargic afterwards she was placed on Ethosuximide and had no seizures afterward until her mother complained she was having stomach issues. So the Ethosuximide was titrated down and dc’d and depakote was prescribed that’s when everything went out of whack. She started having these absence seizures (she did not have when we was taking the Ethosuximide) all day long in school and some at home I only witnessed two however her mom says she had observed some also She was started back on the Ethosuximide injunction with depakote. Recently had eeg done and did not show any epileptic activity - depakote was titrated down and discontinued, still taking Ethosuximide. She is still having these absence seizures at school, no where but school. Teachers time and write down and supposedly can last up to twenty minutes. So I went up to school and sat in class within her to observe ( Im a nurse also ) however she did not have any the whole time I was observing. When I left around lunch she had some that afternoon. We only get her every other weekend and we have noticed every Sunday night we have her she will wake up 3-4 times and state her head and or stomach hurts and this child is wide awake. We have asked her multiple times if something is wrong /nervous about anything but all we get is nothing. She stays with her mother during the week so we do not know what is going on all the time. Just trying to see if anyone else has had this experience could it be sleep deprivation (def thinks she needs more sleep) separation anxiety , acting ? We just can’t figure out why it is only happening in school. ( she went to summer camp at this school also and did not have any issues and no seizure all summer long)