Hi, thank you for your feedback. I would check first if you didn't forgot to enable the rich markdown plugin and check this checkbox that is essential for my theme to work properly:

Currently I'm on an older version of Joplin but I'll will try the theme with the current version this evening and come back to you as soon as I know what's going on.

But just in case here you can find always the last version of my theme:
https://github.com/gonzalovsilva/joplin-dark-theme