What is causing the excess curing around the supports?

I’m printing on a moai 100 with an FEP vat using black resin with the setting being the standard FEP recommended. what’s causing this excess around the supports base?

the firmware is set to overcure the initial layers and squash them so the model can adhere well
this excess layer is not a problem, though be careful that it may leave small debris if the build plate is not cleaned clean