My browser is acting weird

I don't think this is normal I was looking at a thread I clicked refresh. It "refreshed" to an even older page then what I was looking at before. Two posts were gone. I hit refresh again and it went back to normal. This has happened in the past to. Whenever I log on to an account 1 out 2 times my browser crashes. Does this happen to everyone's browser or is just my version of IE. IE is up to date.