Hi
I assume you have now set up the cam timing properly from your previous post.
You never answered if you used a new diamond washer, if not used and the cam and gear is not done up to specified torque it WILL move.
Yes we have also seem an injector come loose after the retaining bolt pulled out the helicoil repair thread from the head.
The injector had moved around so much when it came loose it damaged the injector and the head so badly they needed replacing.
Were new stretch bolts used ?
Did you or the engine builders put the injectors in, sounds like the thread was bad when they we refitted ??