Needlepoints/spikes when slumping
It would seem to me that perhaps you are slumping at too hot of a temperature. The glass should not be fluid enough at slump temps to cause spikes. Ditch the preprogrammed settings, and derive your own firing schedules.
In my kilns, I typically slump at 1225 deg F. You’ll have to experiment, as your thermocouple may be reading low if what “has always worked” no longer works.
You can knock the spikes off with diamond hand pads. With a light touch and a fine grit, it should be unnoticeable.
Jester’s Baubles Fused Glass Designs