Thank you for reaching out.

From the picture you shared, it looks like the bush bean plants showing signs of either bean rust or bean common mosaic virus.

Bean rust is a fungal disease caused by Uromyces appendiculatus, spread by wind-blown spores, and favored moderate temperature and high humidity. It thrives when leaf surfaces stay wet for extended period from dew, fog or overhead watering, as well as overwinters in infected crop debris left in the soil. It causes leaf drop and lower crop yields.

https://www.umass.edu/agriculture-food-environment/vegetable/fact-sheets/bean-rust

https://hortsense.cahnrs.wsu.edu/fact-sheet/bean-rust/

On the other hand, if it is bean common mosaic virus (BCMV), it is a viral pathogen that causes this type of puckered, blistered, downward-curled distortion with green and yellow mottling. Leaves can become stiff, malformed and heavy textured. It is primarily spread by aphids or infected seeds.

https://www.canr.msu.edu/field_crops/uploads/archive/E2894.pdf

If your plant is still producing healthy crops, the pods are not deformed, twisted or discolored, though it has slowed down its production, I would suggest to remove the infected part of the plant and wait for the plant to finish its production for the season before removing it at the end of the season. Water at the soil level rather than overhead to keep foliage dry. But I would not plant beans in the same spot, it is better to rotate locations with non-host crops. Also choose rust resistant bean varieties if you can find them.

Hope it helps.