Problem with F4s in T-Mode and MC-12A...

[Chappelle]

Hello,I just tried to take a couple of long exposures with my recently acquired MC-12A cable release. I put the F4s in T-Mode and hit the remote.After 4 minutes I hit the button again but nothing happened. I tried both shutter releases on the camera, tried to shut off the camera... nothing.Only when I turned the shutter speed dial to a different speed, I heard a click and the shutter closed.All the other modes work with the MC-12A and the camera usually works as it should.So it can't be the cable release and if it would be a mechanical failure with the camera why would it work with the first push and not with the second.The shutter seems fine, it never gets stuck.Does somebody have an idea?