I had a similar problem. I tried to put my Keen Targee 2 boots in a bowl of water but they kept toppling over and I could not find an easy way to hold them down into the water either. I solved the problem by removing the liners and placing them on top of my wheely bin in the garden. I then filled each boot to the top with water and waited......................, within a couple of minutes water was oozing out from various places from both boots. This showed me that my books leaked rather than just being a problem of sweaty feet.
I have solved the problem (not sure if it is permanent or temporary) by pressing in silicon glue (from Halfords £4.99) all along the seams and along the join between sole and uppers. I am still furious to be sold such lemons and even more furious (I should have know better) at the 'erberts' who write as unbiased and independent testers, who recommended these boots as No 1 buy. Also the soles are really dangerous on slippery flat or irregular surfaces, on a recent hike I slipped and fell four times on wet Pennine Way slabs.