Q.About purple hull peas
Is it normal for purple hulls to produce in cycles? Mine will flower and produce very well. Then they seem to go dormant for a while then start flowering and producing again. I guess I expect them to produce like okra does.

This is not unusual in pea production. Likely environmental conditions are effecting the plants.
Harvest can spread out over several weeks.
https://www.gardeningknowhow.com/edible/vegetables/black-eyed-peas/growing-black-eyed-peas.htm