OmniPro IIe lighting control

I have an OP-IIe controller that controls my security, HVAC, and a small system of Simply-Automated UPB devices.  Less than 20.  Everything has been bullet-proof for years, then one day my lighting control stopped working. Everything else is fine.  I can control every lighting device from the wall switch and from UpStart, as designed.  I can also operate the first light in the system (Kitchen Main) from Snap-link and from the HAI panel.  But nothing after that works with Snap-link.  Also, I have very high signal strength and very low noise at every device.  Even though I can operate one of the devices, I have assumed that the PIM was in good working order, but it was recently recommended that I should swap this out.  It is an HAI PIM.  Does this seem reasonable, or could something be messed up in the PCAccess programming, even though I have not changed anything  in years.  
Please keep in mind that I don't work on this on an everyday basis, so I consider myself a novice relative to you folks.  So keep that in mind with your response.   :wacko: TIA


Here have only utilized HAI UPB PIMs with my OmniPro 2 panel over the years.  Initial implementation over 10 years ago started with a defective UPB PIM.  Replaced it and I was good to go.
Today have a number of spares / floaters just in case. 
Over the years have also added an HAI repeater (which is identical to the PCS repeater) which is different than the UPB phase coupler which I used at one time.
One UPB PIM is connected furthest from the panel via a serial to ethernet connection implemented mostly just to check signals with Upstart.
So yeah I would try a new HAI PIM and see if that works for you.