This thread is resolved. Here is a description of the problem and solution.
Problem: When using domain per language and you try to change language, it tries to load the css files from https://URLURL/wp-content/uploads/maxmegamenu/style_da.css?ver=2343b2 instead of https://URL/wp-content/uploads/maxmegamenu/style_da.css?ver=2343b2
Solution: See Relevant Documentation
Relevant Documentation: https://wpml.org/forums/topic/language-url-format-change/#post-3542069
This is the technical support forum for WPML - the multilingual WordPress plugin.