The pressure at PT-124 (just past GV6 along y-arm in LVEA) is the lowest is has been in 10 years. We know of a small leak on GV6 stem flange joint on bonnet plate. I won't read too much into this though knowing many of these cold cathode gauges are originals from iLIGO and out of calibration.
Could also be a Beckhoff thing creating an offset.