Not sure if this has been reported before because I have vague, near Deja Vu memories of it, but when you salvage advanced enemy energy weapons, the capacitor recharge tech received will not actually go towards a full tech grade, but only advance towards the next increment faction. See screenshot:
Instead of getting the full upgrade to capacitor recharge 4, you only advance towards 3.25, even though it presumably costs just as much research. (I managed to advance focal and frequency tech by 1 full level with the same batch of salvage after all)
This is further proven by the fact that I continued to get tech points to capacitor here, but it is not reflected on the tech screen on the right, since it most likely went to a hidden (also likel 8k RP costing) 3.5 capacitor technology.
This behavior possibly has further implications for other hidden fractional techs. Maybe in the future in might be possible to learn max engine size or power factors from salvage or espionage in some way, which will likely fall to the same code trap and instead research every fractional increment (size 124, size 125, size...) before the actual technology.
SJW: Fixed for v2.0