Quote Originally Posted by lat9 View Post
OPC's observer class (which performs the session-hash) doesn't include $_SESSION['shipping']['extras'] as being pertinent to the hash.
But if the condition was understood correctly, on the initial run through of the hash, wasn't $_SESSION['shipping'] not set to begin with? Thus the first cycle would not have that session variable and then when checking for the change, the extras key would be removed but now the shipping session variable would be present?

I say that because of the fix that appeared to work for the OP.