Feedbback coming from headphones

I am having issues with feedback coming through my headphones and bleeding into my amp. This just started happening earlier with no signal chain modifications. For reference I’m running the fx loop to my Peavey head. I have been playing the fx loop preset without any issues, but today I needed to modify my overdrive in a scene to match the same scene as my plugin preset. I have attached photos of the grid views for reference. Once I switched back to the fx preset I started having massive feedback coming through my headphones and a faint feedback bleeding into my cab. Using any of the Gojira plugins gives me this issue. When switching to presets that I created that utilize the fx loop I do not have those feedback issues. I checked ground of the power supply and switched to a different outlet with the same issues. Checked all of my cables and they were all good. The only thing that fixed the issue was lowering the volume from the multiout to 0dB. When I check the Gojira plugins the multiout volume is set to 8dB for all their plugins. Any ideas?