In 87071, we found that the low frequency SQZ noise could be removed by changing the ZM4 or ZM5 PSAMs and we left the ZM4 PSAMs at 6.2V strain (from 6.0V). 

Today I went back to the noisy area at 6.0V and lower on ZM4 and saw no increase in low frequency noise, plot attached. I did not try going higher than 6.2V yet, we could do that as 6.5V caused noise on Monday too. 

It is not surprising that this noise couldn't be re-created as it was coming and going in the past.