Did you have a frost in your area? New leaves on trees are very susceptible to frost and a frost can kill the leaves, but leave the tree healthy. The day after the frost, the leaves may have appeared fine and the damage, such as brown or blackened leaves, may not appear until 1-2 days later.

Another possibility is that the tree got overspray from a weedkiller. If someone was spraying something like Round-Up on a windy day, the spray could have drifted to the tree and may have cause leaf die off like that.

In both cases, the leaves should regrow without a problem.