I found a workaround, which works for me, and probably would for anyone else, just it's a bit complicated. All of the instructions below are for Google Chrome, but shold not differ to much for other browsers too. So the problem is that some localized versions of the JS files are missing from paypals servers, but it still wants to load it. When you stuck on the "checking you info" screen, right click the page, and click Inspect. The debug window will open. Select Console from the upper tab bar. Here you will see a red error message about a missing script, in my case it was https://www.paypalobjects.com/web/res/cf5/5e812dc5909040b91ec1d4881a942/templates/HU/en/rememberMe.js Copy out the URL, you'll need it later. Download and install a Chrome plugin called Requestly. Click it's icon besides the URL bar of the browser, which will open it's settings. Click on the green + icon on the top to add a new rule. Select the "Replace host" option. Type some arbitrary name in the "Rule name" field. Next, check what is the next part after the "templates" part in the URL. For me, it's HU. Type this with / around (so /HU/) to "This part in URL" box, and type /US/ in the "Will be replaced by this string" field. Next, you will need to type the URL part from the beginning to the end of your locale string, in my case https://www.paypalobjects.com/web/res/cf5/5e812dc5909040b91ec1d4881a942/templates/HU to "Leave this field Empty to apply above modifications to all urls" . Save the rule and ejoy :). So it basically redirect your locale to the US one, which works. A screenshot of the rule for help:
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