I could be mis-remembering, but seems like there was a discussion ??12-15 years ago about fan clutches leaving the factory empty (no fluid) on purpose (in the past) which were meant to be filled with silicone fluid before they were installed??
I can assure you AISIN aftermarket fan clutches are intended to come with fluid in them. Fwiw, we stock ~20 different AISIN fan clutch’s for Land Cruiser applications and have sold 1000+, I can’t say I’m familiar with one that was short oil out of the box. I’ll have to ask my guys that cover tech/warranties, it’s certainly possible. We buy AISIN direct so we are guaranteed authentic parts and ideally fresh build fan clutches given the volume moving around the globe.