Thank you for looking at the interation count, probed the VI and found that the problem had to do with timing. You were correct that the loop should only iterate once, however I had this problem with the test fixture I was connected to:
The 'Take a measurement' loop was able to run 3 times since the voltage remained greater than 2V for 100 ms. During this time, the condition was true making it able to stop the loop and proceed through the sequence structure. I added a delay in the second sequence so that it waits while the input signal in the first sequence while loop falls back below 2V. See image.