Take the airplane up and at about half speed, do an inside snap roll. If it does it, then try it with the elevator at low rates if you've setup dual rates. If it does it on low rates, then you've got way too much elevator throw rigged. Nothing wrong with the model other than your setup of it. Yak's are supposed to be aerobatic, and snaps are part of the performance envelope. But a very sensitive elevator doesn't have to be. Simply adjust the elevator rigging. Move the pushrod connection in one hole on the elevator servo arm and test fly again. Or if the pushrod is already connected to the inner most hole (which is very doubtful), move the elevator horn connection out one hole and test fly again.

Simply assembling an ARF by the Chinese instructions doesn't complete the job. Even ARFs deserve proper flight tuning before making the final judgement of their "flying qualities".

I'd suggest that you also use geistware's online application to see where a sensible CG would be for your specific model. It's quite easy to do. All it takes is a yardstick. Measure the 7 measurements and plug them in. It's way more correct than even the mfg's manual's information. Then go test fly and see what throws the elevator really needs.

The mfg's suggested throws aren't sacred. Matter of fact, they're very often incorrect.

An elevator induced snap is about the easiest problem to solve that we face. And very often, the solution for many fliers is simply to program some exponential into their TX.

In the meantime, put a couple more clicks on the TX throttle stick when on final, and don't firewall the airplane on takeoffs. Give it a chance until you can tune it. Dance with who you brought to the dance.