I suspect that the white lines you are taliking about were accross the stress area?
If so these are stress lines not caused by you or anything you are doing but rather by too much stress being put on the nails (usually a sign that nails are too long) and the product pulling up a little product each time they receive a knock. Usually the nails are also very dehydrated as well.
Seeing this damage is precisely the reason why I changed my product many years ago to a product that was more flexible and kinder to the nail. Usually products that employ a primer and are very hard facilitate these stress lines.
If you are concerned by the look of these nails as I was, change your product to something less harsh, where less prep is needed and a kinder product that is more like the natural nail itself.