Geez. Some individuals were posting ridiculous misinformation this year in the Vietnamese and Cherimoya FB groups. I think they're not the originators but they're the victims of that information.
Here's my clarification for what I heard
1. A pollinated flower is not going to "disable" its own pollen so that you can't use it to pollinate other flowers.
2. Taking pollen from a pollinated flower will NOT make the fruit abort.
12Zodiac, if you hear something else, please feel free to post it and the experienced people here will tell you which one is right.