Powered rails randomly become unpowered

I believe that powered rails have a small chance to become unpowered if they are connected, via other powered rails, to a power source that is in another chunk. Say you have a redstone torch in one chunk and powered rails leading away from it into another chunk, they may become unpowered randomly. The issue is resolved when the rails are broken and replaced, but the fix is only temporary and may happen again. Reloading the world also temporarily resolves the issue. This bug has occurred twice in my world, once in the current version and once prior to Chase the Skies.

The expected result is that one redstone source can supply power to adjacent powered rails up to eight blocks in each direction.

The actual result is that the power does not propagate through all eight blocks in a given direction.