Koku Istambulova was a Russian woman who claimed to have been born on 1 June 1889 and lived until 27 January 2019, when she died at the claimed age of 129 years & 240 days. Doing a little investigation today, I found that she had a daughter who died in 2014, aged 104. Now given the fact that Mrs. Istambulova was outside the maximum difference for an longevity outlier...

119 + 5 = 124

(Excluding Calment)

129 - 119 = 10

...I am going to go with the scenario that she was probably confused with her daughter, and that the supposed "daughter" that died in 2014 had gotten mixed up with a close relative. If she claimed that her daughter died in 2014, aged 104, this puts her birth at 1909 or 1910. It is my final opinion that Mrs. Istambulova's daughter's birth records were actually hers and that when she died in 2019 she was probably 109/110 and NOT 129.