- The scope appears to be drifting significantly and the ROI moves away from the sorting chamber.
- you may not have taped down the chip sufficiently tightly and it's possible it is the chip itself that is shifting rather than the stage or the scope.
- be sure to turn off the "start up mode switch" once you've reached a reasonable SS since you occasionally will get a picture with no cells for whatever reason, and you don't want it to accidentally turn off the sorting because of that. Might be better to have the start up mode be based on a moving avg, so an outlier can't flip the switch. Though in theory the startup mode should just be for the first 20ish hrs at the most, so not a huge deal as long as you turn it off for the actual run.