Due to an investigation into this issue on discord we've identified a possible issue with the caching process of compiled JS assets taking a long time.
The cause originates from a previously running hosting environment that offloads compilation from your own hosting environment but which was taken down.
As a result beta7 first tries this remote host and after a time out of 60 seconds move on to the fallback.
In order to temporarily patch this, edit
replace it with:
protected function minify($source)
Please note this issue is most likely caused when curl is installed and available to php.
When debug is enabled compilation is done every single time.