"Perhaps they attribute it to "rounding errors" like maths problems 😂"
You may joke, but it does appear that this is the case.
I just has a look at the "Basque" percentage and it says:
Basque
1%
Your ancestral region estimate is 1%, but it can range from 0 to 1%
In other words, it is equally likely to be zero.
Interestingly, for my Norwegian ancestry which is also said to be 1% it says:
Norway
1%
Your ancestral region estimate is 1%, but it can range from 0 to 3%
So the 1% seems to be midway in this case. There is a much greater spread. In the previous version I did also have some Norwegian heritage and this does seem to have carried over.
This actually makes some sort of sense.
Ancestry is much more biased towards English speaking countries. Our DNA has also been uploaded to MyHeritage and it was interesting looking at the results.
Most of the matches were British, US, Canadian, Australian, NZ etc but there were also a lot of European matches as well.
For example, on Ancestry my mum has 24,000 DNA matches. Where locations are shown, it's all USA, Canada, Australia and New Zealand.
When we uploaded her DNA to MyHeritage there were only 11,000 matches but there were matches in different countries.
This included 174 currently living in Germany, mostly 4th or 5th cousins with between 8cM and 35cM of shared DNA . I looked at some of the trees and they had been in Germany for generations, although some did have obvious British ancestors more recently.
There were also 132 matches in the Netherlands with similar amounts of shared DNA.
After that there was:
Sweden - 124
France - 118
Denmark - 110
Norway - 109
Ireland - 62
Spain - 22 (although most of these seemed to be Brits who had moved out there)
Switzerland - 19
Austria - 13
Belgium - 12
Finland - 12
South Africa - 11 (again, mostly British expats)
After that, there were people living in lots of other random countries but it was obvious that they were mostly Brits who had emigrated there at some recent time in the past (although I did find some odd things, like a Russian woman living in Japan with shared DNA).
But there were definitely some countries, like Hungary where there were four DNA matches that were very Hungarian, and two in Poland who were very obviously Polish, where there was no obvious link to any Brits.
All of these links were really distant with usually less than 30 cM of shared DNA.
So, MyHeritage is a good place to look if you suspect that you have some European ancestors.
My father also had very similar results with European matches.