Creatures with a given type of Natural Attack cannot have more of them added.
For example (using custom created content) if a character has a Tentacle attack from the Deepspawn feat, adding NATURALATTACKS line for a Tentacle attack from another feat (such as Illithid Grapple) Overrides the existing NATURALATTACKS (including things like number of attacks).
This can be circumvented by giving each NATURALATTACK token a different name (e.g. Deepspawn Tentacles and Illithid Tentacles), but this means that other feats such as Weapon Focus and Improved Natural Attack do not apply correctly.
verified on Windows 7, java 1.6, java 1.7
This is working as expected. There are serious limitations to what can be done with the tag as it is really designed to be used once in a race.
A proper revamp is being discussed in