...is propably bent so that it touches the balance wheel when you close the case. There should be a tiny gap between that cover and the balance wheel. If the cover is slightly bent it can come in contact with the balance wheel when you close the case/caseback. See if you can "bend it out" a little. The cover's "mission" ( I think... ) is to hold the battery in the right place/align the battery before you put on the backcase. Hope this helps - keep us updated!