I have human progenitor epithelial keratinocytes that I've used for years from the same company. They usually look like the image in the vendor's webpage, rounded. Recently, after thawing a vial and seeding them in the correct epithelial growth medium into a T25 flask as I have done for years, about 10-20% of the cells have a spindly appearance rather than a rounded one. Do you know what could be causing that? When I [passage them, the new cultures also have the spindly cells. The hood is wiped clean and no other cells are in the hood at the time of passaging, so I don't think it's contamination with other cells.