take a Summoner L14 (pre-existing, don't think it matters) and remove the eidolon.
Create new Eidolon
1) set type = Quadruped, has 1 Bite ... character sheet shows Bite +15/+15 (?because it only has 1 natural attack?)
2) add Limbs (Arms)
character sheet shows Bite +15, and Pincers +13/+13
ok so far.
3) add Limbs (arms)
character sheet shows Bite +15, Pincers +13/+13/+13/+13/+13/+13 .i.e. 6 attacks
That's not right. There's only 4 pincers (4 arms, 2 sets of 2) and max attacks is 6 so I can't add a 3rd set of arms and pincers.
Eidolon file attached
Pathfinder Core Rulbooks (set)
#1 - Look up Animal Companion "Multi-Attack" from the core rules - An animal companion gains Multiattack as a bonus feat if it has three or more natural attacks and does not already have that feat. If it does not have the requisite three or more natural attacks, the animal companion instead gains a second attack with one of its natural weapons, albeit at a -5 penalty.
PCGen would require a massive hack to handle the -5, so the only thing I could do is list "Apply a -5 to the second attack" on the character sheet when this rule is met.
– The other problem is a bit more deep and requires some code intervention. Templatesapplied is showing that we have a "sticking" issue in the system somewhere.
More important to me is the 6 attacks with 4 limbs, 'cos of stacking...
I personally am less worried about the 2 attacks when "only one and MultiAttack", but couldn't you trigger the "iterative attack" code?
NaturalAttacks are a completely different beast. Triggering an iterative code in naturalattacks is setting a completely different naturalattacks. Then the next issue is controlling the iterative attacks, since getting a second attack as an iterative vs. normal iterative progression are two different beasts as well.
I have code in place to correct the stacking. My main concern is the templates staying applied, which will grant the wrong number if you chose 6, and then dropped to 4. You've uncovered a double bug.
There is a code bug opened to handle the fact you have multiple same attack templates sticking around that should be removed when the parent granting them is removed.
I removed the 2 pincer evolutions and added them back, one at a time.
the first added 2 pincer attacks,
then second added 2 pincer attacks
making ... 4