Have you notices any little bugs around such as thrips?
They jump off leaves super fast .
The adults can fly around in some species .
Any thier pretty easy to manage with some spinosad, sm90 or h202.
Or just cover up your roots and wait a few weeks to interupt their life cycle of dropping into the roots to make more larva .
Maybe its just from physical damage.
Hard to say bud. Keeep an eye out for 3-4 days and report back