Reason(s)
Toes are pushing on the end of your boots. This can lead to black toe nails.
Solution(s)
Thinner socks and or thinner footbeds will help. You may need bigger boots. Get a reputable boot fitter to re-fit you.
Mark, MBC Technical
It is actually normal to feel your toes on the end. However they should pull away once stood with your knees bent. If they do not and you already have a good footbed and are wearing performance socks you probably need bigger boots.