Every gap should have a player assigned to it. When Tonga is lined up over center, he either has responsibility for both A gaps, or he has the A gap to one side, with a LB responsible for the other A gap.

On plays where he has responsibility for both gaps, if his rush takes him so far up the field that he can't effectively contain both gaps, then he's failing to execute his assignment. This comes back to coaching.

If he only has responsibility for one of the A gaps and a LB is supposed to be covering the other side, it's generally OK to get up the field because you can generally cover one gap regardless of how deeply you penetrate. Without knowing the Gap assignments, you can't say whether Tonga is failing to execute or not. It could be a linebacker who is missing their assignment.