CSV Importer Bug - Selective Amnesia

Whilst using the CSV importer to migrate customers over to Kashflow I have found that the saved mapping function has selective amnesia. By that I mean sometimes it remembers the saved mapping files I made up the first time I used it, other times it remembers the saved mapping files I made up on another day I used it because it had forgotten the ones from the first time, and just now it has forgotten both even although I was just using the first set no more than an hour ago and hadn't logged off!! its a right PITA