Lockloss @ 16:51 UTC - link to lockloss tool
Cause looks to me to be from high winds; gusts just hit up to 40mph and suspensions were moving right before the lockloss in a familiar way.
H1 back to observing at 21:09 UTC. After a few hours, thanks to a lull in the wind, H1 was able to get relocked. Fully automatic acquisition.