Just got a Velobuild TT-023 framset. I had my local bike shop build it up and they're concerned that it's not safe to ride. The front end/stem flexes so much with weight on the handlebars it loosens up the headset. Also, even with everything tightened down, you can still rotate the bars independent of the front wheel.

I emailed the company and I'm waiting to hear back. Just curious if anyone else has had this issue or has any troubleshooting ideas. Thanks!

Why a new topic ? There is already one for this frame.

That is terrible. I had problems but not like that.
Looks like the fork isn´t cut short enough and that the stem bolts are not well tightened.
But I´m sure you have checked all that.
Well I hope that Chris from Velobuild finds a solution for this.