Teleport raiders passing through forcefields?

[Toranth]

Recently, I faced a wave of 1500 Teleport Raiders in one of my frontier systems.  I had decent defenses there, but not in my deeper systems.  So I built force fields over both the wormholes exiting deeper into my empire.

However, maybe 30 seconds after the wave arrives I suddenly get an AI taunt and a Command Center destroyed message.  I paused, and when I went looking I found that several hundred TP raiders had made it into my protected systems.  I checked the wormhole to that system from the Wave destination system, and it was still covered by a (mostly) undamaged force field.  I went back and tried it several more times, and every time the same thing happened.
It seems almost like they are teleporting directly into the wormhole without entering the FF area of effect, or something.

Is this a bug, or this an intended behavior that I didn't realize?  Has anyone else seen something like this before?  I looked in Mantis, but did not see any previous reports about anything like this.

[Nalgas]

I've had them appear underneath a forcefield when more than one is placed over the wormhole they're entering the system through, which is kind of weird and probably shouldn't happen, but they definitely shouldn't be able to exit the system through one like that...unless maybe they're going around in a different direction.  Is there an alternate route to the other systems they're ending up in, or is that the only entry point?  If there's some other way to get there, they might be backing out and taking the long way around, because they're jerks like that.

[Lancefighter]

i seem to recall this happening briefly before I quit playing..

I used to rely a lot on wormhole forcefields to bar units from going through wormholes i dont want them to go through, but I imagine if the game is running coarsely enough, the check for displacement by forcefield is checked after passing through wormhole, making it kinda silly.