Upgraded to discourse version 2.8.0.beta7 & beta8 causing data loss of </head> section scripts that hasn't been loaded most times in browser

Lots of things changed when switching to ember cli. New installs will default to Ember CLI builds in Productionmight provide some clues.

I think that even if you didn’t enable it explicitly, some of the changes made to prepare for it may be what is causing the problem.