Power Query Sorting by Date not sorting correctly

I have a strange problem I can't seem to figure out.
In the first image is the loaded output of my Power Query query with the ApptDate sorted from oldest to newest. The sort has been manually applied on the column.

Capture1.JPG

In the second image is the preview of the query in the preview window that pops up when you hover over the query.

Capture2.JPG

In the final image is when I refresh the loaded table which should replicate the first image, but it doesn't.
You can even see the sort indicator at the top of the column remains.

Capture3.JPG

I have to manually sort the column again to get it to look like the first image.
Any ideas before I go stripping my file back to share?

Ah - funny, but I had something like this myself the other day.

What you have to do is clear all filters from the table in Excel in order that the PQ filter settings carry through to it. I'm not sure if tweaking the table's external data properties will make any difference.

OK - let's have a look at a sample file, then.

That setting is selected automatically now in the 365 version. The issue I had was at work, where we have the desktop version.