Simply by chance I happened to notice the Diode Chiller warning light flash red momentarily on the laser system status screen. I informed the operator (Jim W.) and went to take a look. i watched for a minuite and it happenmed again so I added 500ml. I'm not certain if it could have taken more but it seemed as if it was just at the threshold that maybe the turbulence was barely tripping the warning.
So, I think from the plot, it looks as if it hasn't been happening for a long period of time.