Question Why cubemaps are just 4K ??

Hello!
I should create an 8K cubemap from an 8K panorama image for my VR PC application.
So, I import the image, I set its shape as "Cube", and I set its max size to 8192.
The big problem is that the resulting cubemap is just at 4K resolution, not at 8K.
Is there some special trick to get an 8K cubemap, just like it was supposed to be?
Any help would be much appreciated.
Many thanks!!

 

Did you set max resolution on the texture to 8k?

 

yes, I did