This came up. We play 3/6 FL with blind of 1/3, button raise and SB puts $1 chip on top of his $1 blind and then decides to muck his card. He wants to take back the $1. Yes or No?
If there was no verbal declaration, and assuming his blind is over any imaginary betting line, then he indicated a call by putting another chip on his blind. Even though it's short the required amount, it's still a call and he owes another chip.
EDIT: OK, now I see there was a raise in front of him so he's not just calling. Then I think this falls under the rule that if you make a mistake in calling when you don't understand there was a raise in front, you can take back the call and fold.