Child's Samsung HP alerts time limit reached when he power on his HP in the morning

Norton Family is installed in son's and daughter's HP. Both devices are Samsung HP and were working fine for months. My children will shut down before they sleep. Since last week, when my son power on phone in morning, Norton Family will alert that the time limit reached. This alert locks his HP. But I note that I do not receive any alert on my HP/email that the time limit was reached. It only appears on his HP and locks it. His Norton Family app version is 6.3.0.11 (same as my app) & timezone is set as Malaysia (same as my app). Strange thing is that my daughter has the same Samsung HP as my son's (Samsung Galaxy A32). But my daughter's Norton Family is working fine. I checked and found that her app version is 6.1.0.8 (different from ours, and I refuse to update the app despite prompt to update). Is there an issue with the latest app version 6.3.0.11? Please help.