Hi Stiofan,
Thank you very much for looking into this and a temporary fix.
Currently, we are not going to need to fill in the custom fields on category pages, but this functionality might be useful in future.
What is a bit confusing in this situation, is that the theme is made by the same developer — Cubell — as Valenti Theme, which many users on GD forums have recommended. I have contacted Cubell and waiting for reply. Let’s hope there is a fix for this situation in the nearest future.
Thanks again for excellent support!