[IMPORTANT] Never complete their technical task until you are sure that they really want to work with you!
I was in two stages of interview
1) HR interview
2) Technical task (home work)
First interview goes well and i was asked to do simple take home task. It was simple but it required FE and BE so even configurations and code takes a few hours to finish.
I have no idea what can be learned about principal engineer by using this task, because it did not require any deep knowledge, but anyway, i finished it and got rejected next day ("Unfortunately, we have decided to proceed with other candidates whom we believe are even a bit closer to our requirements for this position.")
If you have other candidates that are closer to your requirements, then don't ask other candidates to spend a few hours of their life on home task!!! It is not a Junior Position where you have no idea if person can actually write code.