FPS drop while Minecart runs

FPS will drop considerably when a Minecart is moving on rails (powered rails, rails, and a detector rail), most noticeably when the Minecart hits a block and reverses direction - each time it reverses direction)

What I expected to happen:
Minecart will run on rails and reverse direction with minimal/no affect on FPS
What actually happened:
When a Minecart run on rails and reverses direction, FPS drops.