Don’t concern yourself with the ethnicity results unless a significant portion of your ethnic heritage is direct conflict with your ancestral tree. Even if there is direct conflict, it means that you should:
- Review and critique your paper trail for errors.
- Look at your shared matches. Are there individuals you cannot figure out? Are there close relatives you have no idea who they are?
Determine the exact genealogical relationship with as many of your first and second cousin matches as possible. Continue this work on third cousin matches.
Reach out to known cousins (whether they are “into” genealogy or not) to see if they have done a DNA test at the same location you have. Is it possible that they’ve tested you and that you are not DNA match with them? That’s a bigger genealogical problem than the 2% Russian you have in your tree. Don’t assume that if you cousins tested that they would be on your list of matches. They won’t be if for some reason they are not actually biologically related to you.
Generally speaking, work on making your tree as complete as you can and on determining the relationship to as many DNA matches as you can.
That’s better time spent than trying to “reverse engineer” your ethnicity at AncestryDNA to figure out “where they got it.”