Disappearing text messages after unlocking iPhone 15

I have an Iphone 15. Not even a year old. When I turn my phone on in the am, I see several text messages on my lock screen but when I unlock my phone, they are gone. They never come back. It's like they never existed. I was able to screen shot this and take it to Apple store after several unsuccessful attempts with CHAT. The phone was checked for hardware problems, and nothing was found, so they blamed it on the VPN. That was removed. A week later, it happened again. There is no VPN to blame it on this time. Now I am also unable to take a screen shot of the lock screen when this happens, but I can take one once the phone is unlocked, but of course, those text messages are forever lost. It can't be my network, because my husband has the same phone on the same network and NEVER has had this issue.

I'm getting very frustrated and if any one can offer help, I'd be so grateful. The Apple store is quite a drive away, and I really hate to have to keep running back there. Thanks!

[Re-Titled by Moderator]