I would say no, it is not immediate. From my coaching days, the LT was taught, "1 thousand 1, 1 thousand 2", then cut. That is not an immediate, initial action.
Taught to watch the entire block. If we have to 2nd guess what we see, most times you will see no flag. The LT's immediate, initial action is towards that 3, so I would say that is legal.
I hope this helps.