I religiously treated leather. You cannot treat leather to point that it will not soak up water, unless you coat them in rubber or some other non breathable material. If you could treat leather and seams to point that they did not leak, then what would be point of gore tex liner. Leather treatment prevents cracking from rot and absolutely makes boots last longer, but please do not think it will stop once liner leaks.
I thought thing same or at least convinced myself it would. 3 days in high country with damp feet sucked. Merino socks only thing that allowed me to stay on mountain. Miserably but at least in game
I suspect issue with both pair of my boots is the stitching through the liner. Some of the holes seem overly large as all of seep point are along seams.
In may case (size 16 boot) I may have gotten boots from same production run even thought received a year apart so may have been with just that run. They only fire up production to make the bigfoot sizes one month a year as I had to wait on first pair to be made.
When I finally draw a tag in AZ you will likely see these on my feet. I still will wear them. Comfortable boot, never rolled an ankle in nasty blowdowns. Just leak......
I am going to try Gore tex warranty out and see what reaction is from them.
I recommend simple test, a few weeks before hunt. Take out you boot insole and fill boot with water. If your leather shows any damp spots then you are at risk of leaky boot on hunt.
Lose your feet on high country hunt, blister, wet feet etc and see what happens. You will not want to go uphill.
Boots are one the most critical piece of gear you have. Don't believe me have failure. Horrible.