Just to clarify because the ticket repro steps seem conflicting: even if the locale on the test page is set to Swedish when you load the page and browser language is English (United States) the number column interprets 12,4 input value as 124 when you complete the edit so I'm not sure this has to do only when changing locale during runtime?
I added a gif illustrating this problem and a screen capture from chrome language settings as attachments to this post.