Well, it looks like the bug was embedded in my saved games, which were created without the Project Nevada DLC plugins. I just reloaded my last save in the Mojave, entered OWB, and used the console to get back to the Big MT / Y-12 area, and the Master Trauma Harness attacked me without the sound glitch going off, so it looks to be fixed now that I've restarted OWB with the PN plugins. Thanks for the tip on those, I had just installed Project Nevada but had never heard about the plugins. Shame I'm going to have to listen to the whole damn robot dialog again, but it's better than a game-crashing screeching zombie thing.