Yes it shows focus shift and the correct reason it given. (Heavy chromatic aberration) To compensate for this there have been extra markings on older SLR-Lenses because you could not see IR on the viewfinder and the used IR-sensitive film could not be checked without developing it.

Besides using a Stereo Camera setup you could take pictures with and without the filter. Maybe by rotating it between 2 closely timed shoots. Another possibility would be tocheck old table Books on Optical Engineering and search for a matching depth of field at the higher F-Stops. But taking in account the longer exposition times for the IR pics this could be tricky.and lead to over-/underexposure or/and bluring through movement.

There is another way - you could move the focus point with so called pinhole glasses, also known as stenopeic glasses and even use such type of lens with a bifocal grid.