I've Come To The Conclusion That Pam Was Crazy.

[LMLDallas78]

Even Patrick described Pam -- at least, I think he meant Pam -- as "pigstick nutty."

But then, especially in the earlier years, the character of Pam was less clearly defined (until Victoria's acting solidified) and Pam was used by the writers to push the plot along in whatever way they needed. Which made her .... inconsistent.

I agree with that and the same can be said for other characters and there were many really that were inconsistent whilst Dallas was becoming established.
I guess it depends if that inconsistent behaviour is believable for the character and well portrayed by the actor and therefore easily accepted by the audience.