Just did another test. Restore everything from backup, apply lastest joomla update 3.4.5, check that everything work fine. Start install update 3.19 and replace current 3.18 files. Open browser and got the same issue.
Your css and js files are still compressed and I need to see js files uncompressed. Please make sure both template and Joomla general caching and compressing options are turned off and leave it this way for few hours. Maybe its some kind of cache issue,
From what I can assume, you are having css and js compresion enabled in template settings - advanced settings section. You need to turn it off for me to be able to check whats wrong.
I restore my site from backup to the latest working condition which is 3.18. JS and CSS compression is enable on a production site and it work fine with version 3.18. I will send you a link to copy of my website where I have a problem.