You didn't mention if it happened every time you came to a stop. If it only happens sporatically, the AC compressor could just be kicking on at the most inopportune time. That would accelerate the engine while it's trying to downshift. It won't damage anything but it is bothersome when it happens.

Remember to keep your foot firmly on the brake while stopped. Several members have posted near fender benders because the VX will start creeping forward when the compressor kicks on.