Diddy Files New Appeal, Says Judge Acted as 'Thirteenth Juror' with Harsh Sentence

Diddy's legal team is ripping Judge Arun Subramanian, accusing him of crossing a line with the 50-month sentence ... and acting more like a juror than a judge.

Diddy filed a new appeal late Tuesday evening, demanding his conviction be overturned, and his release from prison ... or, at the very least, his sentence be lightened. While his lawyers have previously filed multiple appeals, this one singles out Judge Subramanian for acting as the "thirteenth juror" in Diddy's criminal trial.

In the docs, lead appeal attorney Alexandra Shapiro claims the judge's "draconian" 50-month sentence is based on the conduct for which the actual jurors acquited Diddy -- namely, the racketeering and sex trafficking counts.

Shapiro claims Subramanian incorrectly said during sentencing he could consider Diddy's behavior related to the more violent charges -- even though he'd been acquited of them -- which she calls a violation of Diddy's constitutional rights.

Diddy's insisting his sentence should only be based on the 2 counts of violating the Mann Act -- transporting individuals for purpose of prostitution -- for which he was convicted.

In previous appeals, Diddy's team has also argued he did not actually set up the travel or payment for the male prostitutes ... and, therefore, did not violate the Mann Act.