It could be some residual CO2 releasing from solution. I usually degas after racking when stabilizing to minimise the release. See if it doesn't almost stop in a couple of days.
The sorbate doesn't kill the yeast per say but sterilizes them so they can't continue to multiply. They wind down and die of old age soon though. The campden releases a gas into the wine to preserve it.
Any ideas/feedback
Linear Mode
