Zoysia lawn-round spots
Had a new Zoysia lawn install last spring. I now how round spot about 3 inches in dia. fill with fresh dirt. The first one show up about a month ago, I now have 2 more in the last few days.
This could be moles, vols, gophers, or anything that burrows. This article will help you to control this issue: https://www.gardeningknowhow.com/plant-problems/pests/animals/mole-control.htm