Affinity Booster Not Applying Correctly In Missions

[PsychoticHeaven]

Ok so I use Spy missions to Forma weapons, and have been doing so for a very long time. Ive gotten used to how long it takes me to rank a weapon to 30. I rank mastery fodder with spy missions etc, so its not ALL forma! It takes 3 runs on Kappa with a booster for primary/secondary and 1 run with a melee weapon for me! Since Fortuna, 3-4 times Ive had to make 6+ runs to get a primary/secondary to 30 with a booster running! Thats what it takes without one! Just now it took 5 runs to get my Vasto Prime to 30 with a booster running! Heres the kicker, yesterday I built my 3rd kit gun and after guilding it, it literally only took 2.5 runs to get to 30!! Almost like too much affinity was applying. Thats the second time thats happened since Fortuna as well! It seems like the booster isnt working at times, others its applying too much. Maybe I missed something or someone could explain why this happens...or indeed its bugged! Ive never ONCE had this issue and Ive been playing solid this whole year! I run Loki  Prime w/ Carrier and ONLY the weapon Im ranking! Its not a loot thing(Affinity Orbs)..I rarely even open a case, I just check for Ayatans. Those orbs dont even make a difference in the grand scheme of things so its not those!