incorreckt external links in Combination with Shortpixel AI Plugin

Hi, i have several Error 400 for some assets of my site using the Shortpixel AI CDN. I reached this out to shortpixel and they found out it’s more related to Swift Performance.

Here is their answer:

“The issue is that when Swift Performance extracts the critical-css, it removes the site domain from local URLs (e.g. https://staging.stadtkirche-elbingerode.de/wp-content/uploads/Stadtkirche_Elbingerode_01-800×272.jpg becomes /wp-content/uploads/Stadtkirche_Elbingerode_01-800×272.jpg) but it does this in a naive way so URLs like https://cdn.shortpixel.ai/spai4/ret_img+v_77/https://staging.stadtkirche-elbingerode.de/wp-content/plugins/easy-foundation-shortcodes/fonts/foundation-icons.eot become https://cdn.shortpixel.ai/spai4/ret_img+v_77//wp-content/plugins/easy-foundation-shortcodes/fonts/foundation-icons.eot and get corrupted.
The fonts that have their URLs corrupted are from its own minified cached CSS (processed correctly by SPAI):
https://staging.stadtkirche-elbingerode.de/wp-content/cache/swift-performance/staging.stadtkirche-elbingerode.de/css/e1186fbc534a958bfb91997d7c431cfc.css

This is why the problem disappears when Swift Performance is disabled. I skimmed through their options but I couldn’t spot one that would disable this url “optimization” .”

You can get admin access if needed.
I have no HTML, CSS or Script optimisation enabled.
So i only can decide to turn off Swift or Shortpixel.

The page I need help with: [log in to see the link]