The codes definitely state remove all motive power in the case of an E-stop.
A VFD e-stop in the FWD command is definitely not code, it requires the recommended contactor drop out.
The Haas I have worked on have a 24v control circuit for the system stop start that engages the spindle controller. and main power.
I guess you don't have the contactor on the VFD supply as just about all the VFD manuals suggest, including Huanyang?
You will probably see the requirement for Safety Relays in the future, as is required in Europe.
Al.