Tested some more and it appears that laser guided shells are completely unable to target lasers, but has pinpoint accuracy on cursor position. It worked in 2.00.

I did a little testing myself and i figured whenever you point your cursor onto the ground near your vehicle it will hit the ground directly next to it, if you however point your cursor into the air it lands where it's supposed to land.

Additionally Laser Guided / Guided will never land on a laser target or search for a heat signature if you fire it manually (without the artillery computer). If you however use the computer it works.

It could be worth testing this with the laser guided cruise missiles too. I had an incident a while ago where a missile was supposed to overfly my position en route to a laser target, but landed on me instead. I wrote it off as a fluke at the time, but this issue would perfectly explain it.