Does anyone else get trapped in shifts?

So I was on a pack meet today and that one boy starts having a shift. He always shifts really long so we didn’t worry much when he didn’t stop even after 2 hours (pretty normal, he always shifts between 1 and 2-3 hours). After 2 and a half hours he started scratching with this hand on the sand (we do our meets on a clearing with sand floor) and we realized he was spelling out „help“. Then he wrote „shift“ and „stop“. We realized he couldn’t stop shifting, but had kind of a conciousness. We tried to show him pictures of himself and play voice messages he recorded but he always ran away. At some point he just layed down on the floor. We could ask him yes/no questions, two times barking means yes and once means no. He said that he didn’t really control his body but still had somewhat consciousness. He said that he couldn’t get out on his own. He said that he was scared and that he had to get out. After like half an hour he slowly got out after we talked to him the whole time. The question is now, is that normal? Has it happened to any of you guys that you couldn’t get out of a shift? He also said that he gained consciousness much earlier but couldn’t control himself. Is what he experienced clinical therianthropy?