They’re all 85mm lenses (or close enough with rounding). The likely patent for the RF 85/1.4 VCM has it as an 82.6 or 82.9mm f/1.45 lens, but similarly the likely patent for the RF 85/1.2 is 82.3mm f/1.24. The explanation is not a difference in real focal length.
I eschew YT videos (DIY home repairs notwithstanding) but I did scrub to the ~7 min mark to see it was a noted in a focusing speed comparison with objects arranged in a table and in a portrait comparison. The reviewer failed to provide the proper technical explanation, which is unfortunate but unsurprising.
What’s really going on is that the focal length of a lens is specified as the distance from the rear nodal point to the sensor with the lens focused at infinity. When a lens appears to have a wider FoV (shorter FL) with closer subjects (as in the YT reviewer’s examples), that’s due to focus breathing. That’s why, for example, the EF 100/2.8L Macro has the FoV of a ~68mm lens at 1:1 magnification.
Canon touts the 85 VCM as having minimal focus breathing, which is desirable in a lens intended for hybrid use (lack of focus breathing is one of the reasons cine lenses are so expensive). Focus breathing is not necessarily linear with subject distance, and I suspect what’s happening with the 85 VCM is that Canon’s design puts most of the breathing closer to infinity, so there’s relatively little change in FoV with subjects at different ‘normal’ (for people) distances. Doing so is facilitated with modern focus-by-wire lenses where a microchip instead of gearing is controlling focus motor movement.
.
