Hi,
Well, if you have the 4.4.0 in the file and you have the 4.3.0 when you access the file with the URL, it means that you indeed have some caching of the file, either with the CDN, or another mechanism and that cache needs to be flushed so that you also have the 4.4.0 via the URL (since the pages of your website rely on the one accessible via the URL, not the one accessible on the hard drive.
And no, it's not a javascript conflict. It could have been, but after checking on your website yesterday, I found that it came from the version of the file which just doesn't have the new function necessary for that button to work.