Here's my convoluted understanding (which is possibly completely wrong).
Note: this is NOT with "Include Legacy Sounds" selected!
CS-80 V4 & V3 are separate apps. V3 presets installed in the V3 preset directory do not show up in V4. EXCEPT in the case of previously installed 3rd party Analog Lab preset packs with V3 presets, which already reside within the Analog Lab preset directory. These will show up in CS-80 within Analog Lab (V4) but require that V3 be installed to use. (If you open CS-80 within AL, V3 is brown while V4 is black). They will not show up in V4 standalone. (I personally prefer everything be kept separate between versions. But 3rd party preset packs can install across multiple instrument preset directories as well as Analog Lab itself - this makes meticulous curation exceedingly difficult).