will it be correct to say - “As I had mentioned to you in the past, I have submitted the report to the higher management.” or “As I have mentioned…”
It’s most likely that ‘As I have…’ is required there.
You probably don’t need the article before ‘higher management’.
Hmmm, disagree.
For me should all be simple past (as we know when - “in the past”)…
As I mentioned to you [earlier / before / in the past], I submitted the report to upper management.
or something like … As I have mentioned to you several times already, I submitted it to…
My supposition in answering the way I did is that the mention was in the past but the latest submission has only just taken place.
With the mismatch of tenses , it’s not clear which was expected.