The Defender ATP portal resets to US locale settings on every refresh. It also displays the 'Experience Microsoft Threat Protection' tile on the home page and the blue banner for Microsoft Threat Protection/Try it now. This happens several tiles each day and is becoming a real annoyance. I suspect it should be setting a persistent cookie to retain user preferences and is failing to do so.
On a more general note, please allow us to fully remove US date/language settings permanently and have the product use the client regional settings - this seems to be a common issue across several security portals - MDATP, MCAS, Sentinel. For those outside the US, M/D/Y dates are confusing and unhelpful.