This morning we had a 1Hz instability that started in the LOWNOISE_LENGTH_CONTROL state. 

The next lock we went through this state step by step, and step of reducing the SRCL1 gain from -18 to -7.5 is what started the issue.  Setting this back to -18 seemed to get rid of the 1Hz signal in SRCL, but the oscillation continued to grow in PRG and other channels. 

Then Elenna set CHARD P back to the high bandwith configuration by undo-ing line 4569 in ISC_LOCK, by doing:

            ezca.switch('ASC-CHARD_P', 'FM9', 'ON')
            ezca.switch('ASC-CHARD_P', 'FM3', 'FM8', 'OFF')
            ezca['ASC-CHARD_P_GAIN'] = 80

This stopped the oscillation, then we were able to set the SRCL gain back down to -7.5 without issue, then undo the CAHRD P changes, again wihtout issue. 

We don't understand this, but we have again moved the location of LOWNOISE_ASC in the guardian, so that the CHARD changes will happen before the SRCL gain reduction next time we relock.

Note to operators:  If you see this 1 Hz bussing in the PRG, put CHARD into it's high gain state by pasting the above lines into a guardian shell, all at once.