Do you have the driven tail option on it?

What gyro and servo?

How do you have your tail mix set?

The stock Hawk does not have a driven tail. So if you hit throttle hold while in a hover, your gyro/servo may not react fast enough to hold the tail until all the torque disappears. If you do so while in forward flight, you will find that the vertical tail fin will have enough authority to keep everything in order as the tail will follow in the direction that the heli is flying after the T/R stops turning.

If you do want a driven tail you can add it as an option. But then if your servo/gyro combo is that bad, a driven tail might compound the issue.