That is super strange. I did a bit of research and Safari seems to have a very problematic cache, it will load outdated files even if the cache is cleared.
Can you please try by opening the Web Inspector then going to the Network panel and clicking “disable cache” checkbox? If you keep the inspector open the issue should go away – which would verify the Safari cache issue.
I couldn’t replicate it on my end anymore, both Chrome and Safari works all right, so the only thing left is the aggressive browser cache.