This is almost certainly damage from herbicide. Redbud is one of several plants that is very sensitive to 2,4-D drift. The symptoms yours shows (leaf distortion, cupping, loss of chlorophyll) are consistent with 2,4-D injury. This could be due to someone spraying lawn weeds with 2,4-D on a hot day. It volatilizes into a gas that can easily drift considerable distances.
The tree may still show some symptoms next year, but should be mostly recovered by then, as long as it doesn't continue to get poisoned.