it seems a FEE somtimes enters a confusing state and stops sending data
the current merger requires all FEEs to be active and so this stops the entire system from proceeding.

On MIDAS the page reports the module is "undefined"

On the TTY console (PUTTY) it returns: do_GetState returned z=0 and 8

Resetting the DAQ in question via MIDAS works (Putty logs of the stages shown) and then the merger resumes without trouble.