A bug inside the lens. hmmm. Was it a certified Canon bug perhaps?.. Maybe they're the ones doing the calibration nowadays. If so, I'd wait till it dies, and then send the lens back. Mhuahahahaha...ahem.
If it were me, I'd find a way to take a photo of that. And then make a big deal out of that. Who in He-- did the QA on that before shipping it out?.. I once had to send a brand new camera in, they fixed something, but when I got it back, almost nothing on the viewfinder worked. My first question was, 'you change a faulty shutter assembly, a main board, and you do not even think of looking into the viewfinder before sending the 1D back to me?'... They faxed me a shipping label (overnight), then they fixed it, and overnighted it again. Still, I missed my big shoot with the new 1D, but nothing ever failed again on that camera.
As far as me, nothing is really acceptable in terms of quality assurance. If your kids found the bug by simply looking at it, a tech would not have had such a hard time either.
And the problem with a dead bug is its tiny wings, the legs, it all begins to fall apart and become a bit of dust that you can never quite clean out. Then they charge you for dust on the lens or some crap like that.
Good luck though. (My saying is "A mispelled Lens -Cannon- is good luck, a turd in your salad is just plain wrong"). Nothing lucky about a bug inside your weather resistant lens.