If the mobile phone can't receive the short message, it can be received when it is turned off and restarted.

You can still receive it after shutdown and restart, indicating that the function of receiving SMS after searching the network again is normal.

Whether a mobile phone can receive short messages in time under normal circumstances depends largely on the network environment. Your network should be poor, with weak coverage or interference. The latter is more likely. You can complain to the operator and give it a try.