Crazy signals from laser / VPD RHIC scalers

This morning was saw jumping rates in the minbias trigger:

The start time for this run was 2:54am.   This is a point about halfway through the plot below, where the vpd coincidence goes from 8Mhz-> 9Mhz.   At this point the minbias rate is depressed, but at 2:57 it jumps to its proper rate, while the vpd coincidence from RHIC jumps down to its proper rate for about a minute before fluctuating again.    The RHIC scaler is problem is correlated with the jumps in the minbias scaler. 

At the same time, we can look at the previous run, in which we had the laser trigger firing.   In this case we see that the scaler rate of the minbias trigger was also fluctuating by amounts, but we also see that the laser trigger was malfunctioning.    The first 5 minutes of the run show the laser trigger firing as expected.  At that time the laser was turned off.   

The 1900hz laser trigger is a malfunction and is perfectly correlated with the minbias trigger rate changes.

Furthermore, I added some test triggers on the laser bits in following runs.   We see the same behavior correlated with the laserProtect bit being on:

Where the rates for the laserProtect bit explain the drop