(Please respond to the other, identical, posting here:
https://powerusers.microsoft.com/t5/Building-Flows/No-row-was-found-with-Id-1-however-I-am-checking-against-quot/m-p/646130#M86303.
I created this post, then realized that it is better posted in Building a Flow, so copied the data there. Now, I can't find a way to delete this post.)
I have a iterating primary ID being generated programmatically via variables and expressions, entering static integers into the column, Data ID, such that row 2: Data ID = 1, row 3, Data ID = 2, and so on (row 1 is headers).
Here is the set-up in Flow:

When I attempt an "Apply to each" identifying the Key Column as "Data ID" and the key value as the current value of "Data ID," I see in the run report that Data ID was the Key Column, the Key Value used in the first iteration was "1" then get the error message 404: No row was found with Id '1.'

To my inexperienced eye, it looks like:
I am asking flow to look for a row with "Data ID" to be equal to "1" then
Flow goes and tries to find a row where "Data ID" equals "1" and then, for some reason, says that
it can't find a row with "Id" equal to "1" which is a problem, for some reason.
How do I make Flow look for a row to update with "Data ID" equal to 1?
Yes, Data ID = 1 exists

What key concept am I missing on this? Or, is this yet another one of the many bugs in Flow?
Thank you in advance for your help; it is very appreciated.