It doesn't appear to be the typical M-sync timer problem since it actually fires when switched to X. I had a yashica D that had the shutter stuck with timer and M-syn, and switching to X wouldn't solve the problem as it remained stuck. Finally, following a howto online, I took it apart and removed the timer mechanism from the shutter and that remedied the problem. However, I ended up with an ugly box since the leatherette was destroyed. So, just to make a long post short, just don't worry about it if it works. It will probably continue to work for you for a long while.