Peas do not need—or usually want—”good” soil, which is to say the kind of soil that so many other plants love—composted soil. Peas perform best with little attention. The coffee grounds, especially such a quantity may have upset the balance of your soil, adding nitrogen which encourages leaf/foliage growth. Sounds like a little too much of a good thing. In future, compost the coffee grounds and use the results on other plants.
Peas do not need—or usually want—”good” soil, which is to say the kind of soil that so many other plants love—composted soil. Peas perform best with little attention. The coffee grounds, especially such a quantity may have upset the balance of your soil, adding nitrogen which encourages leaf/foliage growth. Sounds like a little too much of a good thing. In future, compost the coffee grounds and use the results on other plants.