Runner bean question

I water them well twice a day so its not lack of water and I have plenty coming that are fine its a puzzle.

Only have one bean on the runners so far. It’s a bit of a funny L shape. If the beans inside swell before the pod the plant is under some kind of stress. Runners love water so I would imagine it was that week of boiling hot weather that made them bolt.

I have grown mangetout and sugar snap peas. The first glut had large pods before the peas started to swell. I thought they had finished but a few doses of tomato fertiliser and they are off again only this time some of the pods are small when the peas start to swell.
Might it be weather related?

My first crop didn’t materialise so planted a second crop. It was rather late and I don’t have any beans yet but will see. I still have some of last year’s in the freezer!

I had my first few yesterday very tender and tasty. I’m interested to find the answer.

I have noticed this on some of our bean plants too and I am interested to know the reason why. I did wonder if it was a random variety - all our seedlings were killed off by a sudden frost and we had to source replacements from a garden centre. I might actually pick a few for dinner tonight and see how they taste.