I’ve seen this before with younger bucks.. Even buck on buck action, if you are into that sort of thing. I’m assuming its just immaturity and crazy hormones. Think of most human boys at age 14…
The buck sheds his velvet because of the rise of testosterone in his system. As soon a she sheds his velvet he is ready to breed (like many teenage boys at their first dance). The only problem is the does are not. The young bucks inexperience does not know this and thinks all does are. The mature or more experienced bucks know the timing as they have been there before. Similar to the beginning of the rut/pre rut when usually you see the younger ones again chasing does first and then when the timing is just about right is when you see the mature ones on their feet tending.