When you get your DNA test results back, you get two different results.
One is a conversion of data from our autosomal chromosomes into a string of letters (A, C, G, T) representing the state of the genes on each of your chromosomes. This data can be used to compare to other people, to determine if you are related and can be used to compare with known mutations associated with disease. This data is accurate, factual and does not lie.
The other result is your ethnicity estimate, or admixture. The results are based on the company's proprietary algorithms run against your DNA and a set of other people in that company's database that have self-identified their ethic background. This is purely done for entertainment purposes.
So, getting weird admixture results at any given company, or trying to compare results between companies, is a bit fraught.
There are some interesting stories about there about identical twins that have done DNA testing at the same company and compared their admixture results and their ethnicity estimates did not match. It's all par for the course for that aspect of commercial DNA testing.
All that said, I found out through comparing my father's DNA with his matches that his mother's father was not the man she grew up with. Her biological father was the son of an Irish immigrant (to the US). My father is essentially 25% Irish. None of the companies show any Irish in his admixture results, even though he has matches with lots of people in Ireland. *shrug*
You definitely can't take the admixture part of the service to seriously! :)