Piston mechanics change at chunk borders

Steps to reproduce :
-Build this flying machine
-Start it by removing the redstone block on the right and placing it again

What I expected to happen :
-The machine would fly to infinity and beyond

What happened :
-It stopped after a few blocks. When restarted, it worked for 16 blocks then stopped. I retried, and it stopped after either 16 or 32 blocks every time. That seems to be linked to chunk borders.