No serious it true. I have had as a year 1 player who quit just after Expac 1, got taken king dlc a while back. Been getting legendary drops. Upgrading these from say 240-60 or so light up to 280 and my int.dis slightly improves. The number you get is based around the light of the gear. As higher light gear is required to hit tier 5 lv40 300 stat req. Where as lower light gear e.g. lv 34 only needs 170 ish if i remember. Rng are on stats there is min/max rolls. e.g. you see green low level gear with 15 int or whatever. as there is a min max stat for each light level. A lv40 item has a 30-40 ish roll without a perk focus or bonus from rarity. However raiing light through infusion has minimally increased my armours actual stats. i'm only talking 308 int to 315 that has allow me to put more perks on dis my secondary stat.

you would need to post a video for proof, cause I am 99% sure your stats don't increase on infusion

You actual stat value is based on light level. e.g. say a rubish green lv 5-10 item is min max 15-20 or so points. A lv 300 item has a higher min max. by infusing you gain minimal bonus. I seen this happen on multiple items. On my titan. e.g my legs are great.