Minecarts will not ascent a fully powered track more than 9 blocks

Create a staircase made out of Redstone blocks, make it 10 high. Lay powered tracks up the staircase, and 3 blocks in front of the staircase (see attached screenshot). Put a minecart on the start, and give it a push. It will only rise about 9 levels before stopping and coming back down. This doens't happen in 1.7.5.