Lines can not be parallel in 3 point perspective. The convergence can be very slight, but it has to be there. When a set of parallel lines goes away from the viewer, it has to converge in a vanishing point.

The boxes you do with shallow convergence should have the vp far away, away from the page, but the lines should still converge.

Don't restart, keep going and stop drawing parallel lines. Good luck on the rest of the challenge!

When one set of lines are parallel you are drawing in 2 point perspective.

When two sets of lines are parallel, then you end up with one point perspective. In this case the one set of parallel lines has to be perperndicular to the other set of parallel lines (because the side of the box you are looking "face on" has to be rectangular).

If you remember the steps of the Y method, it says that the angle between the arms of the Y shape need to be greater than 90 degrees. This is also saying you shouldn't be drawing in one point perspective (because then one of those angles has to be exactly 90 degrees).

But you can approximate one point perspective while still following the Y method. Just avoid perfectly parallel lines. Instead give them a tiny bit of convergence. Also avoid Y shapes that have one angle too close to 90 degrees. And as one of those angles close to 90 degrees, then the two corresponding convergences should be shallow (while the remaining one should be steeper).

I wouldn't be too worried. You still have a lot of boxes to go. A lot of them are pretty parallel. But then actively attack that: squeeze your convergence angles a bit harder and make the perspectives a little more aggressive. I try to have a crazy one in there every now and then - something that rocks the boat (like your 33).

You have the opportunity of 250 boxes to test the principles you were show and to push your comfort zones. You are definitely feeling solid about the current boxes you have drawn. If you take more risks, I think you'll get what you want from this.

It's fine for some of the boxes to have a very low convergence, however it's never the case that they are completely parallel. It's up to you to experiment with different scales of foreshortening: sometimes you would want to draw objects that are really far away or are really big and close to the viewer.

No need to redo your current challenge, it's a part of the learning process.