Need help identifying root issue(Pics)

image.jpeg I recently flushed a set of 1.5mo+ old clones in soil (1/2gal pots) and in an attempt to help dry the root zone, placed small spacers in the bottom of each pot for 2 days to bring the soil away from the sides of the pot ~1/4inch. A few have developed this condition since. Nothing flying in the room and nothing moving on the outside of the root zone visible to the naked eye. I'd appreciate any help identifying this.
 
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