I suspect I may have damaged some of the 2N2007 FETs on a RELAY8 board, but the failure mode seems odd. The three channels that have failed will not turn off. At power on the red LED comes on, the attached device activates and functions as expected - but I cannot turn off the channels. Other channels behave as expected. I would expect the failure mode to be open, with the device permanently off, but I haven't blown up enough FETs to be sure.

Is this a failure of the FET, or something more bizarre?