I am also confused about what you are referring to.
https://www.youtube.com/watch?v=gCgc8JJMqvY
This video by Lazo (dated October 18, 2016) shows that when Talon jumps over Anivia's wall, it is marked red so that Talon should not be able to jump over it again.
If you are referring to the 2 second cooldown before Talon is able to jump over another terrain, .. that should still trigger, and does in this video, so if you are seeing this not happen, I would say it is a bug.
If you have seen this in a recent game that you have played, it would be very helpful if you could record and upload a clip of it using the in client replay system.