Landrace sativas from Thailand and parts of Africa are notorious for throwing a few male flowers, the so called bananas, in the last two weeks of a long bloom. It is not always a sign of stress, some lines simply do it as a survival trait when the plant senses the season ending. The hermaphrodite notes at
https://hazesativaseeds.com list which regional lines are known for this and how many seeds you can expect to find. Removing them daily with tweezers keeps the damage to a handful of seeds.
