XML checkpoint fails

I am using an XML checkpoint to check a XML file against the source which is stored in TestComplete.

When I run the test, the checkpoint fails. The reason is that the file differs from the source. When I inspect the differences there are no differences displayed.

Firstly, I am not expecting any differences.

Secondly, why can't I see the differences that triggered the failure?

I have included screenshots.

Any help/suggestion is appreciated.

Thanks