It's happened at least 3 time recently that guiding up to the meridian flip was good .5"-.8" but RA went off the charts after the meridian flip. After several recalibrations and changes in exposure times and camera gain, and even redoing the PA (which said it was fine), the graph showed a sawtooth pattern in RA. The only environmental changes were that a nearly full moon was the almost overhead and the temp dropped 2°C. I use an Astronomik CLS filter on my ASI290 guide camera because I live under Bortle 6 skies inside a housing complex with garage and walkway lights. I checked the balance in RA and DEC and they were fine.
Any thoughts on why the guiding changed so dramatically?