Receiving texts that are timestamp in the future

my husband's phone has recently been sending text messages and when I received though it is the moment he sent them they are timestamps the most recent in the farthest 8 minutes in the future from the time it was at that moment it would do that for two messages and then every message after that was timestamp properly and when I received them they would be placed before the text messages time themes in the future and until that actual time came through those messages with stay at the bottom

For example it was 3 p.m. I received a text message that was time-stamped at 3:08 p.m. two text messages were received at that time since they received instantly the very moment he sent every text message after those two word timestamp at the correct time in the two future messages stayed at the bottom as the most recently received message until after 3:08 finally passed it is done this a couple of times we are on the same plan on the TV networks he was within 2 hours drive distance from me he was not roaming we do live in Oklahoma where there are a lot of dead spots and he's been in worse areas with left signal and he's been in this same location for a while now working and we've never had this happen before. What would cause it I'm assuming because Since I'm receiving it from his phone number that he is sending these messages to me from his S9