“All oils are lubricants, but not all lubricants are oil.”
Back in the late 1900s there was just refrigeration oil and the only differences were the viscosity. However, with the advent of non-chlorinated refrigerants, we now have non-oil-based “lubricants” that are being used in place of refrigerant oils and service techs that enter your shops don’t always understand which type they need (they’re not chemists).