R2E2 Fruit with no seed

Slicko starts with ...
I have a seedling R2E2 mango tree that's been bearing for 5 years . The crops have been good and really even in the size of fruit. This year the fruit set was really good and as it developed I noticed that it was filling out unevenly- some were growing more quickly than others. I have now harvested the crop and found 12 fruit to be between 900 grams and over 1.1 kg. The rest of them were small, more numerous, tasty but devoid of seed. The capsule was there but no seed whilst the seed in the large fruit was normal.
I am surprised by this and can think of no reason for this to happen . Has anyone seen this before and know what causes both the difference in fruit size and what seems to be unpollenated fruit set?
Thanks
Mick

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Slicko says...
That's an interesting thought, Fruitylicious. It would be great if I could remember the dates the tree started to flower and then match them with the temperatures at the time. Perhaps then I might be able to solve the problem. Of course no such luck.

I do recall a relatively cold winter and an early start to spring. The stone fruit were early and my bees collected nectar throughout. A good year for honey. So maybe there was an overlap of cold and flowering. Shall have to watch for it next year.

Thanks for the reply.

Mick

Fruitylicious1 says...
G'day Slicko

Might be handy to have a garden diary for future references. I just started mine to keep track of everything that comes to mind. It's a quick and easy reference for trouble shooting next time something unusual comes up. Might also enlighten other forum members with similar dilemma.

As ALWAYS Happy Gardening :-)