Morningstar Relay interface introducing pops into audio signal

I have a morningstar relay interface (plugged into an mc8) that was sending out a tap tempo to 2 walrus pedals with a TRS-dual mono split cable. This introduced clicks into my audio signal when tapping - I tried using just a normal TS cable into one of the pedals and the clicks are gone, so I assume it’s some sort of ground loop issue. Is there a way to split the signal into the two pedals without creating a ground loop?

The ground loop is caused because both devices are now sharing the same sleeve from the TRS to dual mono adaptor. There isn’t any way around this though, if you want to control both devices with one relay interface.

The alternative would be to use a second relay interface to control the second delay.