Backup because for no reason at all it dumps my remember what tabs were opened

I’m just a student learning. This is annoying. Going along many times open and close Ureal5 as I study a bit each day. I have preferences set to remember what tabs I have opened. So they match up with the teacher’s. Always after about a month give or take there will come a day I will open up U5 and blap no tabs opened.

Why is U5 randomly ignoring my tab preference settings?