This year my Fortex beans were only really good for the first few pickings. After that they got bumpy even when small, and recently they've been soft and hollow, rather than crisp and firm. I wonder whether it's just the heat or perhaps I need to find a different variety. They've been my favorites for years, though.
Sounds like bean yellow virus, mottle virus or mosaic virus, sometimes the only symptoms are distorted leaves and pods plus empty pods. Symptoms vary depending upon which stage of growth the plant was infected, especially with bean mosaic virus.