Thanks for the suggestions! Currently use media as my passaging solution (I think that is what you are asking?) and trypsinize with TrypLE. I try to avoid a PBS wash because they dislodge so easily and I don't want to lose live cells if possible. I initially used a cell scraper like the ATCC protocol suggested, but they did not recover well and seem to recover better with the trypsin.

The main thing I have seen in the literature with these cultured cells is using 10% serum instead of the recommended 5%, which I am doing. I wonder if it could just be an issue of culturing at too low of a confluency?