Servo twitching on arm and disarm

I am currently using a 5v BEC (from a 6s source) to power a servo onboard a
hexacopter. this servo holds a package pouch and once activated, will drop the package. We are experiencing servo twitching once armed and disarmed. We tried installing a 1000uf to limit the voltage sag (as what we believed it was) and it keeps twitching. Has anyone ever experienced this before?