Shifter`s Multiattack feat works!

[Grumish]

Shifter`s Multiattack feat doesnt reduce attack penalty on secondary attacks. Its still -5 not -2 as the feat says.

[Deo]

"Your secondary attacks with natural weapons (including attacks treated as secondary as a result of being altered by the Shifter's Fury ability) take only a -2 penalty instead of -5."

It works but in a weird way. For example, on Manticore Shifter - you will shoot 4 attacks with a -5 iterative penalty, and then 3 attacks with -2 iterative penalty (coz of Shifter's Multiattack).

Here screenshot, for example. https://ibb.co/xMp9Trz

Wojif has 25 AB, and 7 Spike attacks (with Shifter's Fury). He attacks Smilodon, does 4 attacks with -5 penalty each (25, 20, 15, 10) and then 3 attacks with -2 penalty (all at 23). As you can see it even shows penalty in description.

I don't know if Shifter's Multiattack poorly worded or just works wrong way. But it's working, as you can see. Just not the way you and I would think from the description.

But yes - for your primary attacks you will have to pick Mythic Feat "Flawless Attacks" which reduces iterative from -5 to -4. It's a pretty good feat, coz for example without this feat you would attack 25/20/15/10 and with it you will attack 25/21/17/13.

[Zuloph]

First up make sure you hit alt+b in game to report any bugs you find, it helps the devs if you do it that way since it will send some game data along with the bug report if you allow it to. Helps to identify and quash bugs faster.

Second, shifter's multiattack only works for secondary attacks. Natural weapons have primary and secondary weapons. Deo already sort of explained this a bit but I'm going to see if I can help shed some more light on this.

If you have a bite and 2 claw attacks for example, those are all primary. They do not suffer any negative BaB but you only get 3 attacks. You don't get more natural attacks based on having higher BaB.

If you use Shifter's Fury to say select your bite attack so you can utilize your full BaB and make multiple attacks with that bite at 6/11/16 BaB respectively then Shifter's Fury makes your claws secondary weapons. Secondary natural weapons take a -5 to hit and can only apply half str / dex bonus to their damage depending on your build.

Now your bite will get multiple attacks and take the -5 penalty for iterative attacks and it's still a primary natural weapon. At this point if you take the Shifter's Multiattack feat it won't do anything for the bite, but your claws will be the attacks to be affected while Shifter's Fury is active since they are treated as secondary weapons. So assuming 20BaB, no bonuses this is what your attacks would look like with Shifter's Fury active

Bite - +20/+15/+10/+5
Claw - +18/+18

I've seen Shifter's Multiattack working just fine in game myself as well. It's worded perfectly fine, you just have to have game knowledge of what is a primary natural weapon and what is a secondary natural weapon.

https://www.d20pfsrd.com/bestiary/rules-for-monsters/universal-monster-rules/

If you go to that page and scroll down (or ctrl+f to) Natural Attacks you'll see which natural weapons are primary and which are secondary in that table.

[Grumish]

Holy crack! It is as you say! Guess i didnt know the rules well enough. Big thanks to both of you Deo and Zuloph!
I guess its a nice feat for Ulbrig after all.