Symptoms of herbicide damage include necrotic lesions on the soybean hypocotyl near the soil surface and reddish-colored spots or lesions on the hypocotyl and/or cotyledons. See:
Soybean Injury from Soil-Applied Herbicides. University of Illinois.
WEATHER AND CROP DAMAGE
Climate induced reduction in U.S.-wide soybean yields underpinned by region- and in-season-specific responses. Nature Plants 1, Article number: 14026 (2015)
Symptoms of Low Temperature Injury to Corn and Soybean - Purdue University
Signs of Drought Stress in Soybean - Purdue University