I'm not sure if this is a known bug, but for me the Laser Rifle beam splitter does not do as it's description suggests (2 beams doing half damage, plus 30% overall damage). Rather than splitting into 2 beams it splits them into 3 and there is absolutely no increase damage output when you multiply the 3 laser's damage together.
Assuming the basic laser rifle damage of 15, the beam splitter should result in this.
9.75 (half damage plus 15%) dam x 2 lasers = 19.5.
Results in a 30% increase in overall damage.
Instead it does this:
5 damage x 3 lasers = 15
Results in the same damage per second but with a huge decrease in effectiveness versus DT.
Using the GECK I changed the Beam splitter to fire 2 instead of 3 beams, but it just produces:
7.5 dam x 2 lasers = 15
Again, no increase in overall damage and much less effective versus DT.
I've tried to fix this bug, but I don't understand how to edit the 'split beam' effect's properties to try and see what's happening.