I asked Perplexity to examine the code and help diagnose the problem.
The skipping of Ancestors for female People of Interest was due to the “Try to remove extra people and families” being selected in the Report Options tab.
One of its tests (in the report’s removeuninterestingparents() code) is whether the person of interest shares a surname with a parent. I suspect that, in theory, this is intended to trim out adoptive parent or step-parents families. But it seems to be too aggressive in practice.
So, the recommended workaround is to disable the Try to remove extra people and families option in the Report Options tab
- (Test case was “Zieliński, Phoebe Emily (Garner)” from the example.gramps test tree. She was the daughter of Шестаков, George and Daniels, Phoebe.)