Minecarts Not being Pushed Up Blocks By Powered Rails

(A clip is provided in the issue submitted to help provide a visual view). I have been continue building a server for my clan and any other people that join the server (which will launch on June 30th, 2014 and will use the recent snapshot versions until the full 1.8 update is launched) and I have been making a mineshaft for the whole server using mine carts in Snapshot 14w11b and they, for some reason, do not automatically move up rails placed upwards (Up to another block). If you hold the up arrow key (To move the cart forward) at all times during the ride, it continues without issues. It acts as if it is not on a powered rail or is being pushed back by an invincible block... Why? I have no clue, but it is a very annoying bug and hope it is fixed. I can't continue my Mineshaft project with this bug being present... This issue happens with mine carts that are summoned by commands and ones that are naturally placed (Item placement)