I've found that's usually an issue with relays more than it is with Amethyst. Have you tried deleting your relays and adding them back in one at a time until you find the stability killer?
Discussion
Is that the best way to go through relays? I've just been deleting them based off the stats they provide about them
For this instance it might be the best just to troubleshoot. This sounds like one of the relays he's using isn't sending back the expected dataformat and causing the app to crash. If you're just looking for most performant then looking at stats might not be a bad way to slim them down.