I am testing my emco vmc100 with mach3 every works fine but i do not understand one thing

I use the g84 for tapping that works oke except that if the tap is at the bottom the spindle reverses but it takes a second or so before the z-axis moves up. I think that should be immediatly?

Thank you for your reply

Tantan
http://m.youtube.com/#/user/tantancnc?&desktop_uri=%2Fuser%2Ftantancnc