You have termites and if your raised beds are close to your house you should take immediate action. Even if the beds are a distance from your house you could be in for an infestation. You can try to eradicate them yourself or hire a pest control company. Lowes and Home Depot sell products specifically formulated for termite/ant control but I am not sure if it can be used in a vegetable garden. There are also baits and stakes that use insecticide impregnated cardboard that are put into the ground. You should check your foundation for a "mud tunnel" going from the soil line up to the sill of the house. Termites do not like light and build these tunnels to exclude light when they travel. If you constructed your raised beds using non pressure treated lumber look there for the colony. You may have to probe the wood surface with an ice pick or other pointed object as their tunnels in the wood are not always visible.

That picture is of a termite but the only time you need to be concerned about termites is if they are within 10 feet of your house, or another wood structure. Termites are here to help get rid of woody waste, without them we would be buried in downed trees. In your garden termites are not going to harm your growing plants.

Thank you both! I did poke around the wood in that one box and found some tunnels so I guess the mystery is solved. Thankfully, the garden is not near the house, it's about 60 feet down the yard. My biggest fear was that I was going to have to dispose of the soil and frame and lose all those plants. They really won't hurt the plants?