Would you mind doing a plugin test? The error that we are seeing on the browser console from your site is not common and we cant replicate it on our end, so we can not say that this is a bug, but more likely with your site setup. If it's not possible to deactivate all the plugins try purging the SG Optimizer cache and deactivate it for a while until we resolve the issue, also if the site is under an internal caching please deactivate it as well. This is to make sure that the site is serving us the updated resources and not a cached version.
Also, I advise to re-install the Cornerstone to make sure that there is no corrupted file due to fail update. The easiest way is to deactivate and delete the Cornerstone, then visit the X > Overview page so it reinstalls automatically.
If this does not resolve the issue, please provide us FTP credentials in "secure note" so we can investigate further.
Let us know how it goes,