Hi, although you found an alternate solution I just "accidentally" discovered a much simpler solution, so perhaps it will help others:
The problem appears to have be that I had marked it as "estimated" in the Q&A but the error-check screen that asks you to unmark it in the form. For some reason this doesn't propagate it back to the Q&A.
When I went to the Q&A page titled "Let's enter <your name>'s HSA Contributions" the value was still marked as estimated (right-click menu). After unmarking as estimated it in the Q&A the error checking passed.
This is with the 2020 Windows desktop version, just in case that matters.
