Messages in banner disappear….

Why is it that sometimes when I receive a text message banner on my lock screen, instead of it opening when I try to view, it just takes me to my Home Screen. When I go my messages to try to read the entire message, it’s nowhere to be found…. This is troubling in that I cannot read the entire text message except the first part that shows on the manner. I have an iPhone 13 mini currently using Ios18. My storage has plenty of room and I do not have unknown senders set to be filtered. I have noticed that it happens mostly with receiving authorization codes sent via text to my iPhone. This has been going on for several months and I need answers!