I sure don't know what's going on but I have very strange matching patterns compared to most of my relatives on ancestry.
On ancestry, I have 65 pages of matches. My nephew has 73; my sister 76; my mom 89. Dad's sister 1 has 92 pages; Dad's sister 2 has 87 pages. My Dad's brother only has 83...9 pages less than Sister 1 and 4 pages less than Sister 2. Interestingly, this uncle has the ethnic profile most like mine with some Persian, Turkish, Caucaus.
On FTDNA, I have 19 pages of matches; my sister has 20; my Mom 24; my nephew 14. Aunt 1 has 16 pages; Aunt 2 has 22 pages. My uncle has 19.
I realize that FTDNA has international tests so a comparison with ancestry is somewhat of an apples and oranges comparision. Still, my results are much more in line with the rest of my family especially my sister.