Virus TI2 and Yamaha FC7 volume/polarity - just switch pedals

Apologies if this is covered elsewhere. I had been using a Yamaha FC7 (successfully) to control the volume for a Virus TI2. I began having issues where the Virus would issue a loud pop - very loud - and all output from the virus was shut off. Restarting would resolve it, but temporarily. I checked the MIDI settings, and with the MIDI volume enabled and set to channel 7, it would work short-term. I found that IF I cycled the midi controls through all settings and back to #7, it would resolve the issue - short-term. I just couldn't rely on it, so I went to a Yamaha FC9 (9 volt battery), and used L and R cables in and out. That worked. Then, I started having flaking volume issues with the FC9. Tried a second one - great at first - then, I had the same issue, and Yamaha (stupidly) uses a 12v adapter for AC. Lo and Behold, I was also having issues with an FC7 controlling a Prophet Xl - no volume control at all, and changing the polarity in MIDI did nothing. I don't know why I hadn't tried this before - I took a Moog EP3 expression pedal from my Subsequent 37, flipped it over, and switched the setting from "normal" to "other," and it works like a charm. Then, I simply bought Moog EP3 pedals. In all fairness - I have used the FC7s for years with a number of keyboards without any issue, but the time I spent between the Virus, Prophet Xl, and a Prophet 12, trying to resolve the issues was worth far more than the $30 more the Moog pedal costs.