Xymon FILE check (hobbit-clients.cfg)

Hi guys - I'm having a bit of trouble getting this check to work. It seems random whether it will work for servers or not.

Some have the check working (and show a green status) however other hosts have the check as clear, so Xymon thinks it isn't defined for those hosts. Thing is, I have other checks defined in hobbit-clients.cfg for those hosts which *are* working, which rules out the "HOST=" part not being read properly.

Any ideas..is this a known issue? Thanks!