Cubemaps with out prefiltering not working

Hi Everyone
Today when I want to use a cubemap that isn’t prefiltered, that unfilter cubemap isn’t showing and ends up being replaced in my materials with the skybox in the environment.
If I switch the cubemap in a material to one thats prefiltered based on the exact same HRD files, it does work, but of course it’s blurry.
Not sure if something changed or this is a bug or user error, could have sworn this was working before.

Thanks for the update Tong, that’s what is happening, so I am doing things as expected then.

Trying to get really mirrored looking reflections, guessing I need a bigger cubemap to achieve that. I set the glossiness to 100 percent and the reflections still look blurred. The original HDR I converted to a cubemap was 2048 X 1024.
Trying a 4096 X 2048 HDR to cubemap conversion to see if I can get a mirror looking reflection.

I can’t because it’s private, but taking the cubemap out of the skybox gave me the result I was looking for.