I’d say it’s about prefered browse and for sure cover near the beans. My beans are bordered with standing corn so the deer feel very safe in there and the wood line is 20 yards away. Your deer may prefer alfalfa, at least this time of year and will switch to the beans when they dry up and the alfalfa freezes.
I have beans at home also and a 60 acre bean field right next door. My plots are definitely getting hit, but they are also spending a lot of time in the field next door.
Grouse might be on to something with he soil type affecting the taste, that is a great theory!
But to contradict everything I have just said, I have never known deer to not like, no LOVE beans as an early and late food source. All my experiences with beans is deer will crawl through broken glass to get them.