OSX Mountain Lion, Mavericks and Yosemite do the same - with Zyxel at home (Mac+Lan, Macbook Pro+Wifi), with Linux Samba discs at work (Macbook Pro+Lan/Wifi).
It's not question of hardware - I see the same behaviour on my Mac, Macbook Pro and Macbook Air.
When I try to copy file to SMB drive...