banpei

Thank you for your replies.
@threadi: I did not find any other errors in my console. I did also find the characterset issue this afternoon, but I didn’t get a similar error in my console.

I managed to fix the issue by purging and clearing all caches (php / memcache / Cloudflare / browser). I already purged all of them this afternoon, but it didn’t resolve the issue then. This afternoon I didn’t purge them all at the same time. Maybe somewhere a faulty upgraded version of a Javascript library was still lingering around?
@kandikills maybe you could try this as well? Make sure you purge all caches at the same time and then try again.