When bees start drawing the comb in a TBH, they usually start as the guide or starter strips dictate. After a few combs are started, you will if it is going to happen, a small bend or curve to the comb. Once it starts, it will continued to develop until its just messed up comb. If you watch every week or so, you can determine this as it develops and take corrective action. And that can be just adding new bars between the already straight pieces, while culling out of moving the other less straight pieces further and further back.
When they do the bending or curving of the comb and it progresses more and more, it can be a sign that the bar width is too wide. But it could also be that the bees just start this as they draw honey comb deeper on one side and then adjust on the next frame, and it goes out of whack from there.
Don't be afraid to change out or add new bars and force them to draw good comb between the straight pieces.