I constantly lose signal on my 18i20 3rd gen.
Power fluctuations are very common in my area, so that's my main suspicion.
This also happens when I turn on some lights, or a fan, so again, I suspect voltage spikes to be the culprit. I'm using a UPS (APC) and a Pyle Power conditioner, but they don't seem to help.

Important detail:
The 18i20 doesn't turn off. I just suddenly stop getting audio. Every time this happens, I have to go into Focusrite control and change the sample rate.

This seems to restart some internal stuff, and it's back to normal. This is happening so often that I made an AHK script to automate sample rate change. But it's really annoying, so I decided to ask and see if there's a solution.

Thanks in advance for your help.

Anyone?

It's not clear what's causing this issue. If you haven't already, I'd recommend raising a ticket with the Focusrite Support Team so they can investigate further with you.

If your power products produce square waves (instead of sine waves) the Scarlett may not like that. Just a possibility.

You need an exorcist.
But until you find one, I think you should get with Focusrite. Did you buy this interface new or used?

Thanks for your input, guys.
I bought this thing new.
I'll try to get in touch with focusrite.