Date Format changes unexpectantly

I have a power query that pulls dates from a US based file location with US based formatting (I'm in the US as well). In the power query editor, the dates appear correct. I even changed the date columns to English-USA using the "Locale" feature, so the dates appear as MM/DD/YYYY.

Unfortuantely, when I go to the regular Excel screen with the data loaded, the date fields appear in DD/MM/YYYY format, and the format doesn't say "Date". It says "Custom". 

I usually have an offsite team that refreshes this form every day, and they are based in an area with the DD/MM/YYYY format. However, even if I refresh it, it doesn't return to the regular MM/DD/YYYY format. 

I cannot figure out why this is happening. Any help would be greatly appreciated.