Are you looking for the answer why or are you asking for a solution?
The Dannye's files you use aren't good friends with the AC files. That's the only explanation I can give.
As for a solution, here's something I did until Dak sent me the right SCM file: when you place a Packer for example, get on your bike and while looking back, slowly drive away. Don't go too far though, it might just disappear again.
Something else that people used to say was that
not remembering it would make it stay.