if it's failing to reset and there's nothing visibly wrong, I'd reach out to timney and ask them to look at it. the trigger group is way too important to experiment with an ultrasonic cleaner, which can strip finishes and lead to corrosion over time. I use the ultrasonic cleaner for steel suppressor baffles, sometimes a leaded 1911 barrel, etc. Not for critical components like an AR trigger. For such areas I would just use compressed air and a tiny film of mil-comm or other grease on the sear-hammer contact surfaces. that's it. lubricant is only there to repel water so as to retard corrosion. whatever you decide to do, call and chat with timney first let them guide you.