I agree. I didn’t notice the significance of the “when you are first awakened” clause, and agree that makes the answer 1⁄2. I interpreted it as “right after site is woken up, be it in Monday or Tuesday”, though that’s in retrospect not what it’s saying, it’s saying “on Monday”.
You know, Wikipedia shows two versions of the problem, one of which uses that clause and one of which doesn’t, and doesn’t note the difference (that I’ve seen). This problem really is a mess of hard to notice ambiguous wordings, with a little bit of philosophy problem underneath.
This feeling is not universal, by the way. E.g. I have no such feeling. So the model needs to explain not only the world (one way or the other), but why some people’s intuition is wrong (one way or the other).
The gap in my mind is at the word “could”: if the universe was re-run you could choose to not to lift your hand, but you would choose to lift your hand.