Does anyone know why my TikTok app removes itself from my phone after a few hours?

It has done this for about a year. I don't use TikTok much so it doesn't really bother me but it's so strange. Sometimes when I'm using it it'll quit and then disappear. I don't think I have any personal settings on my phone to do this. I've looked at time limits for apps, etc and I have none. It is SO weird.