Helix Ulitmate 2.1.0. Template: shaper_helixultimate. I have selected to use a "Custom Style" on the template 'Presets'

What might be happening here? It's causing an error in my page. This line is in the Inspector source of the page:

Refused to apply style from 'xxxx/templates/shaper_helixultimate/css/presets/%7B' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled. <link href="/templates/shaper_helixultimate/css/presets/{"footer_link_hover_color":"#FFFFFF","footer_link_color":"#A2A2A2","footer_text_color":"#FFFFFF","footer_bg_color":"#171717","menu_dropdown_text_active_color":"#ec430f","menu_dropdown_text_hover_color":"#ec430f","menu_dropdown_text_color":"#252525","menu_dropdown_bg_color":"#FFFFFF","menu_text_active_color":"#ec430f","menu_text_hover_color":"#ec430f","menu_text_color":"#252525","logo_text_color":"#ec430f","topbar_text_color":"#AAAAAA","topbar_bg_color":"#333333","header_bg_color":"#FFFFFF","link_hover_color":"#044CD0","link_color":"#ec430f","bg_color":"#FFFFFF","text_color":"#252525","preset":"preset2"}.css" rel="stylesheet">