If you look at the schematic you can see what is happening. That amp has an unbuffered effects loop that is driven off of the preamp volume directly before it hits the phase inverter. It's possible you could be seeing 40VAC or more on that signal if you have the preamp volume cranked. This is in no way an Eventide issue, it an amp design issue. I can't think of any effect in the world that could deal with that signal without clipping if the pre is up high enough without padding the signal
To pad the signal send the 'send' to a passive volume pedal or passive volume knob in a box, then to your effects, then turn the master up a bit to compensate. You can use the peak light on the eventide to know when you've got things right.