At 2:27:09, H1 dropped out of OBSERVING.  Looking at the ISC_LOCK log, it appears we had a connection error in Beckhoff/Slow Controls land (for h1ecatx1 specifically).  Connection was re-established 2-seconds later.

2:27:38 Went back to OBSERVING.

Below is the log for ISC_LOCK showing the connection error:

2020-01-05_17:30:35.886414Z ISC_LOCK [NOMINAL_LOW_NOISE.main] ezca: H1:ASC-ADS_YAW5_DOF => ON: LIMIT
2020-01-06_02:27:09.449357Z CA.Client.Exception...............................................
2020-01-06_02:27:09.449357Z     Warning: "Virtual circuit unresponsive"
2020-01-06_02:27:09.449357Z     Context: "h1ecatx1.cds.ligo-wa.caltech.edu:5064"
2020-01-06_02:27:09.449357Z     Source File: ../tcpiiu.cpp line 947
2020-01-06_02:27:09.449357Z     Current Time: Sun Jan 05 2020 18:27:09.448494623
2020-01-06_02:27:09.449357Z ..................................................................
2020-01-06_02:27:09.514405Z ISC_LOCK [NOMINAL_LOW_NOISE.run] USERMSG 0: CONNECTION ERRORS. see SPM DIFFS for dead channels
2020-01-06_02:27:09.568101Z ISC_LOCK EZCA CONNECTION ERROR. attempting to reestablish...
2020-01-06_02:27:09.568760Z ISC_LOCK CERROR: State method raised an EzcaConnectionError exception.
2020-01-06_02:27:09.568760Z ISC_LOCK CERROR: Current state method will be rerun until the connection error clears.
2020-01-06_02:27:09.568760Z ISC_LOCK CERROR: If CERROR does not clear, try setting OP:STOP to kill worker, followed by OP:EXEC to resume.
2020-01-06_02:27:11.145579Z ISC_LOCK [NOMINAL_LOW_NOISE.run] USERMSG 0: IMC_LOCK: has notification
2020-01-06_02:27:11.193648Z ISC_LOCK connections reestablished