Minecarts Disappear When I log Into My World

OK. I did skim through some of the Minecart bugs that were reported and did not see one a duplicate of the bug I am talking about.
Whenever I log into a my world I find that my minecarts, hopper minecarts, tnt minecarts, minecarts with a chest, etc., disappear. I though I was going insane but after the 5th time it happened I knew it was a bug.