1. When Alex is telling Karl to go warn the Losties, did anyone notice the flashing yellow "light" above Karl's shoulder? It was something in the background. It was probably nothing... just a reflection or something. But, it's the kind of thing that usually drives a camera operator nutzoid. If it was unintentional, somebody should have stopped the camera and yelled, "What the hell is that flashing thing spoiling the shot!?" If it was intentional... what was it?

2. When Bernard is demonstrating his shooting ability, the background is so totally and obviously a landscaped area. It a "natural" landscape design, but still fake. Poor choice of location.
(OK. This one is catty, but I hate when stuff like this takes me out of the story.)

I thought the first one was a fire that Karl had going in the cave he was hiding out in.

Just rewatched the episode. It does appear that the flashes were Karl's campfire. Simple explaination. Still distracting. #1 solved.

for #2, I'm pretty sure they were still at their beach in that scene, right near Eko's church. That area is not landscaped. They might of added some extra foilage, but I doubt it was landscaped. It's Hawaii. ;)

The flashing light in the bamboo stand behind Karl bugged me too. At first I thought it looked like some kind of signal beacon, because it seemed to flash at regular intervals. Then, a little later in the scene I realized it must be just a campfire. Still, it looked kind of odd at first and was definitely distracting during the scene between Karl & Alex.

I didn't notice anything too unusual about the target practice scene. I'm sure the location they chose needed a bit of art direction, though, to turn it into a makeshift target range.