I have noticed that some fire is targetable, though I cannot see any reason why this would be...
Pets attacking lava is a known issue. You can stop them shooting it by setting them to passive mode.
Other than that? Pass.
Warning:
The above post may contain Cynicism, sarcasm and/or pessimism. If you object to the quantities contained, then tough.
i've seen pets attack a van parked next to sharkhead ferry 
no matter what the bots did that van didn't move though
That's because occasionally Scrapyarders (and possibly others) escape through the vans. Sometimes they don't disappear though, only the graphics are gone, so you get invisible enemies that won't fight back, but your pets can attack them.
Icelock - Ice/Storm Controller
Command Bot 1 - Bot/Traps MM
I first noticed this when playing my robot/traps mm, i came across some enemies and some fire. I told my pets to attack the enemies but they just attacked the fire.
no matter how much i told them, they were detirmined to attack this fire. after i had killed them all i set the pets to defendive mode. they just sort of looked at me for a few seconds and turned back to the fire.
Has anyone else noticed this?