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Given that dichondra prefers loose, clod-free and well-drained soil, I would work on improving the soil. I have linked you to several articles that will help you below:

I would also ensure that you are meeting the plan of care (watering, fertilizing, etc.) that is outlined for dichondra at:
https://www.gardeningknowhow.com/ornamental/groundcover/dichondra/growing-dichondra.htm

How to improve clay soil:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-to-improve-clay-soil.htm
https://www.gardeningknowhow.com/special/organic/how-to-easily-improve-your-clay-soil.htm

Improving compacted soil:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/improving-compacted-soil.htm

For more information on the care of dichondra, please visit the following link:
https://www.gardeningknowhow.com/ornamental/groundcover/dichondra/growing-dichondra.htm

These areas could be infested with pests, such as moles or other underground rodents. You can take samples of soil to your local extension to find out if you have any deficiencies, or if your pH is out of balance in your soil.

Here are a couple of links that will help: https://www.gardeningknowhow.com/extension-search/
https://www.gardeningknowhow.com/ornamental/groundcover/dichondra/growing-dichondra.htm

Could you upload a photo so that I can better see what is going on? This could be many things. Can you tell me a little more about the environment around it?

My research isn't clear on this, though it seems to be reported it would be only once a season.

If grown as a lawn alternative: One of Dichondra's many attractions is that it requires LESS frequent mowing than lawn grasses. It will look neater, however, if mowed at least every two weeks and this will also help to control weeds. Set your mower to a height of 1.5 to 2.0 inches during summer months. Close cutting (3/4 inch) when temperatures are cool encourages dense small leaved turf. Don't' remove too much growth at any one cutting or when you wait too long to mow.

A heavy leaf litter mulch will impair sunlight that is needed for the new growth. Raking may loosen and disturb the minimal rooting of the young dichondra, so I would recommend a blower to remove the leaf litter. But direct the force of the blower air across the surface to lift and blow the leaves away, and not down into the surface too hard where you may blow soil and dislodge weakly rooted plants.