As described in linked ticket SUPPORT-8176 (thanks to Federico Navarro for his information):

We've tried recently to add the #compress Freemarker directive to a page template, and as it turns out, this seems to be breaking the rendering of subcomponents when navigating to them via selectors.
Eg (same selector uri in both cases: selector uri: /simple~mgnlArea=content~ )
Without #compress in page template:

For short, using attached lightdev module info, this URL is not gonna be rendered correctly (missing a bit of text at the end):
http://host:port/your_context_webapp/simplecompress.html~mgnlArea=content~
What in the compress file lightmodule1.zip :

1. An exported XML page - website.simplecompress.xml
2. A page template folder with its yaml and ftl
3. A component template folder with its yaml and ftl
4. Put them to your lightdev module, import the page to page app, access to the URL to reproduce the issue.