Yet Another Rails Bug: Sloped detector rails and powered rails randomly flip

What is it:
When you place powered rails (p), detector rails (d), normal rails (r) and whatever block (b) like this:

Side 1:
r___r
bdpb
Side 2:
r___r
bpdb

and place a minecart anywhere, and push it. The rails will start randomly flipping directions from the normal angle to a slant up in the middle.

I have an example (and it's obvious how you do it) right there:
http://youtu.be/65E--EL4BrI

I'm sorry if this is a clone, I did scan through the "Rail Bug" serarch in the bug tracker.