I had a problem with bore butter one time when I was living in Vermont. It was a sunny winter day and the temperature had risen to about 11° if I recall correctly. Went to a quarry a few miles from my house and went to set up some targets, but left my hammer behind. So I leaned a few things against the wall and then proceeded to load my rifle. I pulled the bore butter out to lube the patch and the darn tube was frozen solid. So I took that tube back up to the target area and used it to hammer in the brads I'd brought to mount some paper targets.
then I'd put a patch in my mouth (spit patch) and after I poured the powder down the bore, I put the patch on the muzzle and my lead ball over it to finish loading. As long as I didn't put the patch down before putting it on the muzzle under the ball, it loaded and fired just fine. So the bore butter was pretty worthless in freezing weather for its designed function, but sure made a good hammer for mounting targets in freezing weather.
And then I came back to the Muzzleloading forum to see what folks used in freezing weather, came across Stumpy's Moose Snot formula, and have been using that paste patch lube for the last 20-years. It doesn't freeze in freezing temperatures and doesn't turn into liquid during the summer either. it's about the consistency of paste shoe polish.