Doesn't the NEC Counterclaim dismissal without prejudice leave the door open for them to reopen those counterclaims.

From your post:

"Therefore, the words without prejudice protect the plaintiff from a defendant's res judicata defense."

In that case, isn't it saying that a dismissal "without prejudice" protects a plaintiff from the defendant claiming the case is already "a thing decided" (res judicata) and therefore can't be tried again. Since the plaintiff is protected from that defense, it means he CAN bring these claims back, doesn't it?

Secondly, on the NEC counterclaims, while they are the defendant in the case that PTSC/TPL brought against them, aren't they in essence the "plaintiff" in the COUNTER claim, and thus PTSC/TPL the defendants.