Slides not displaying content

I've got a issue with slides not showing any content to users, only when I take them as a admin I can see the slides content, similar to the issue discussed here: https://www.opigno.org/en/forum/support/slide-not-showing-lesson-after-…. Tried the solutions there, but seems in manage display all settings are correct. other users can go back and forward in the lesson but will just see a blank white slide.