Shoot out rails were always meant to undock after a direction change, and they did in most cases. Only when it kept changing direction per block, it didn't do that (allowing your fast logic clocks to work). This bug was about them undocking too soon, they should undock after a direction change, not before it.
To fix that, now they'll undock 5 updates after they encounter a direction change I believe.
You can still use your rail logic clock with normal rails, as they're supposed to be used with permanently docked entities.
I'm sure that some point we'll ramp up the minimum speed (or its maximum speed) when physics improve further.