I’ve had two scopes fail in hunts. An older Weaver Classic 4x fogged internally and was unusable. It never cleared and went in the garbage.

A Leupold VX-II 1-4 had a seal let go and formed a yellow haze. While still usable, it was hard to see through. Leupold fixed it and it has been fine since.

Both days were snow, freezing rain, rain back to snow

My brother had a Leupold ring break (front ring if that matters) on his 270 while shooting at an elk. Not sure if it was user error or a defect. Either way, a pisser