It’s not really a bug. You can only claim vehicle expenses on a car which you used for business purposes. If you didn't use the car at all, or if you only used the car for personal use, you can't claim vehicle expenses as a business expense. So those km boxes can't be left blank.
In your case, you also a have a disposition to add to the bottom part of the form. But because you didn’t use the car you can’t save the form because the top part of the form can’t have zeros. So my suggestion would be to just put 1 km total driven and 1 km drive to earn income. That should allow you to save and continue to the next page, and it’s a small enough value that the CRA probably won’t have an issue with.
And on the next page, don’t take CCA. The CRA may question why you are taking CCA on a car that you did not use for business purposes.
