Lockloss @ 22:31 UTC after 11.5 hours locked - link to lockloss tool
Caused by S-waves from a M6.1 EQ out of Venezuela. Happened less than a minute after the start of the transition to EQ mode, so I didn't get a chance to try the ASC Hi-Gain feature to ride through it (although, in this case I don't suspect it would have helped). Holding H1 in DOWN as it's still 10 minutes before the R-waves are supposed to hit.