Did the Umpires make their 2nd mistake of the series in the 4th T20?

Ultimately, I don't think they did.

England have contested 7344 deliveries in India over 4 Tests and 4 T20 games. Over the first seven matches, the umpires have made one mistake - Ajinkya Rahane was incorrectly judged not out upon review in the 2nd Test match at Chepauk. In the 8th, they might have made a 2nd, but then again, they might not. Washington Sundar was given out upon review, caught by Adil Rashid on the boundary. Here’s why this was both interesting and doubtful. Ultimately, I think the correct decision was reached even though I initially thought it was incorrect.

The point here is not that Rashid’s heel is touching the boundary rope when he catches the ball. It’s not, because in the next frame, the ball reaches the fielder and the fielder’s heel loses contact with the boundary rope.

Two laws are relevant. First, Law 19 which governs boundaries. Second, Law 33 which governs the Caught dismissal. The relevant portions of the two laws are given below.

19.4.1 The ball in play is grounded beyond the boundary if it touches
- the boundary or any part of an object used to mark the boundary;

19.5 Fielder grounded beyond the boundary
19.5.1 A fielder is grounded beyond the boundary if some part of his/her person is in contact with any of the following:
- the boundary or any part of an object used to mark the boundary;

33.2.1 A catch will be fair only if, in every case either the ball, at any time or any fielder in contact with the ball, is not grounded beyond the boundary before the catch is completed.  Note Laws 19.4 (Ball grounded beyond the boundary) and 19.5 (Fielder grounded beyond the boundary).

The MCC produced this animation to explain the boundary catch.

The basic point is that before a fielder makes first contact with the ball, the fielder cannot have been outside the boundary. If the fielder has stepped outside the field of play, then the fielder has to first step back into the field of play and then make contact with the ball. The fielder can ultimately complete the catch in several parts (and even involve a 2nd fielder), but in each part, whenever a fielder is in contact with the ball, the fielder must first be completely in the field of play.

Was Rashid in the field of play? This is debatable. When his heel touching the boundary sponge (as Daniel Norcross insists on calling it) he was “grounded beyond the boundary” under the definition in 19.5.1. When his heel lost contact with the boundary sponge, his front foot is still in the air, and he’s essentially standing on his right tow (which is clearly within the boundary and not beyond). So, at this moment, does Rashid stop being beyond the boundary? Or does he have complete the step?

If we consider how boundary fielding is judged in cases where the fielder is sliding, then even if the fielder has made contact with the boundary sponge, as long as there’s no contact when the fielder is touching the ball, this is considered a legal stop - i.e. the fielder is considered to be within the field of play. Rashid’s situation here is equivalent. That’s why I’m inclined to think that the umpire was right in concluding that once it was clear that Rashid was not in contact with the boundary sponge he was within the field of play, and the catch was complete.

The umpire was right again. Its still just one mistake in 7344 deliveries for the series. A superb record.