I have green beans growing in a grow box in new potting soil on my 2nd floor...
I have green beans growing in a grow box in new potting soil on my 2nd floor deck. Leaf edges seem to have sun or frost burn and the whole leaf gets dry, brown and falls off. I haven't been able to see any evidence of insects.
From your description, the foliage of your bean plant is probably suffering from environmental stress. Temperature fluctuations and wind can really batter spring foliage. The browning of leaf edges is most often symptomatic of inconsistent soil moisture, and the same symptom can occur as a result of either too much or too little water. Don't hesitate to replant beans throughout the summer season.