I clip gained the recording in Pro Tools to get an audible level for the video demo. Any preset sounds perfectly fine at any setting without reverb.That's a much better demonstration, thanks. It's interesting that your input clipping has gone away in this clip. I wonder if that's a clue.
You must have the output cranked to get an audible signal (or the gain turned way up in your DAW)? Don't turn your Input Gain down like that, that's in the digital domain, so it won't have any effect on input clipping. Similarly, you can introduce input noise when you turn the sensitivity all the way down like that. Leave your sensitivity at no lower than 10% and leave the Input Gain at the default neutral value. Otherwise, you're processing a signal with extreme signal-to-noise and that might be causing problems with the reverb, but that's just a guess.
Instead of mucking with the input settings, I would take the guitar and the input A/D out of the equation entirely. Use a synth block in front of the reverb to generate a tone.
As for the input gain and sensitivity all the way down: I wanted to try an extreme setting. At factory default settings and slightly lowered input gain/sensitivity the issue still occured. In fact, the glitching/artifacting didn't increase or reduce any. It just is present whatever I do, so as long as the Reverb block is engaged. It's really mindboggling.
I will try the synth block suggestion tommorow, thank you! That should be an interesting test.