Thank you.
The name {data} is also in your revision, then you haven’t used it in a formula and so it seems all right, but it’s not okay, because if I wanted to use it it wouldn’t be possible.
I believe we now know that {data} should not be used as a formula field name
I edited all 42 submissions by re-entering the datetime value in a new field with a different name.
And then I redeployed the xlsx form without the {data} field anymore.
I hope this post will serve others to avoid this undocumented detail
