Addressing Recent Stability Issues

Why not take pics of every exp you get before and after the buffs? Becouse i think it goes like this: normal exp: 100, 3x exp= 300 (doesnt matter if it is 3x or + is the same thing). now if you add HS you get 50% more so you need to get the 50% of 300 and thats the extra exp you get: 50% of 300 = 150 so now you get: 450 exp.
Now lets add 1.5, 1.5 its like adding 50% more exp so with this you go have to get the 50% of 450: 225 so now it adds up to : 675. Now if you add the 2x card it would be: 1350. so instead of multiplicative or adding yous calculate it with % its easier to understand it.
1.2= 20% more (familiar buff), 1.5 = 50% (like hs). Well that is how i understand it

So in other words it's multiplicative. since anything *1.5 is the same as 150% of any number.

On the topic of EXP I think over the weekend I hit some sort of EXP multiplier cap. While using a WB mule, HS, 1.5x exp legend buff, 2x card and the 3x event when I deactivated HS I gained around 12k exp at Roids activating HS I would get 1 exp per kill. - Has anyone else seen this?

The exp multiplier cap is 8x, anything higher and it reverts all exp to 1. 3x *2x = 6x, 6x * 1.5x(HS) would make it 9x exp. which is above the 8x exp cap.