Welcome to LE.
Any brand of glass can be shocky and turn into frit-on-a-stick. As Kathy said, a little preheating helps. Sometimes. Some glass colors are just a PITA and will cause problems no matter what.
There are several methods: wave in and out of flame for a little while; place rod ends into kiln - careful w/this one when taking out as entire rod may be hot if in too long; put rods in an aluminum cake pan or on a rod warmer plate on top of kiln - also be careful as above; buy a piece of equipment called a rod warmer.
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