Is it intentional that if Parvati puts the basic "Receive a +2 state token" switch on herself in active turn, she'll be unable to use it fully because the effect will degrade to +1at the end of her activation? In other words, is the only way to get the +2to use it during a defense roll?
Correct! Similar is Unlimited Power for Hexx3r, during her turn she takes the -2 which will then degrade to -1for her next activation.
No, " A Target cannot be under the influ- ence of two or more instances of the same State, unless otherwise stated by the State rules. If a Target would be giv- en a State they already have a token for, remove the first State token and add the new one, red-side up." In the core set only the poisoned state can stack.