It's the part where Alpha Trion revitalizes the Matrix and restores Hot Rod to his Rodimus Prime form, and then Rodimus and Optimus team up together for the first time.
Here's a comparison between the three different subtitled versions of this scene:
Metrodome DVDs
Alpha Trion: "Rodimus, lift up Matrix!"
Alpha Trion: "O Almighty Matrix, resurrect yourself with cosmic wisdom and power!"
Unspecified voices: "Rodimus Prime!"
Another voice: "Rodimus has come back as a Commander!"
Narrator: "Behold! A dramatic moment in history! The birth of Double Optimus Prime!"
TV-Nihon fansubs
Alpha Trion: "Rodimus... Let me return the Matrix to normal!"
Alpha Trion: "Use the energy to recharge the Matrix! Revive the power surpassing the Wisdom of the Cosmos!"
Unspecified voices: "Rodimus Convoy!"
Another voice: "Rodimus has become a Commander again!"
Narrator: "Did you see it? The most dramatic scene of the century! The birth of the dream! Double Convoy!
Shout! Factory DVDs:
Alpha Trion: "Hot Rod, lift up the Matrix!"
Alpha Trion: "May the Matrix of Leadership light out darkest hour!"
Unspecified voices: "Hot Rod!"
Another voice: "Hot Rod has been reborn as Rodimus Prime!"
Narrator: "Behold! A dramatic moment in history! The combined strength of two Primes!"
That second line of Alpha Trion's resembles nothing of what he really says, being nothing more than a case of fanwank forced in as incorrect translation. Not to mention the typo of "light out darkest hour".
And it most certainly is not stated by the narrator to be the "combined strength" of "two Convoys/Primes", but rather that it is the "dream-like birth" of "Double Convoy/Prime".
And what's more, this isn't the only case of this kind of change. Fortress was given the name "Cerebros" in the subs, when he is an entirely different identity from G1 Cerebros. He's as much Cerebros as Ginrai is Optimus.
Sixshot's title of "Decepticon Dinobase Ninja Staff Officer" is renamed "Phase Six Decepticon officer", using a term from IDW G1 that has no place in this show.
All cassette Transformers are subbed as "Deployers", which isn't even a G1 term!
The unspecified energy that was recharging the Matrix directly referred to as Plasma Energy, thus removing any mystique and wonder behind the unknown energy that would help to empower the Matrix. Not to mention that this is well before any of the character even hear about Plasma Energy.
Episode titles become wonky in the translation. "Four Warriors Come out of the Sky" is subbed as "Warriors from Space". "Behold the Birth of Double Convoy" is subbed as "The Rebirth of Rodimus Prime". "The Great Cassette Operation" is subbed as "Operation: Autobot Deployers". And so on and so forth.
"Scrap" is used as an expletive, over any typical choice like "darn", "blast", "curse", "drat", etc.
Slang terms such as "Autojerk" and Decepticreep" are used where nonexistent.
The meteorite named Metemorphose is subbed as "Metamorphosis" And its magnetic properties are redefined as gravitational properties, which is utter nonsense given the context of that episode, since it deals with it having an influence on metals.
In some later episodes on The Headmasters DVD set, they actually CUT OUT some lines of dialogue, none of which were even slightly offensive. So much for these being uncut releases.
Even later episodes in The Headmasters feature subtitles that make mention of such non-G1 subjects as the "Pit", the "Inferno" (early name for the Pit), and even the "AllSpark", which does not exist in the G1 cartoon (the one from Beast Machines was spelled "Allspark" with a lowercase S. The uppercase S spelling specifically deviates the two from each other).
And, according to the Evolution of Transformers animation panel at SDCC 2011, there will be even more changes made to Masterforce and Victory.

They're gonna be using the English names for characters in Masterforce who are entirely different characters from their American counterparts. Like, the Decepticon Pretenders Blood, Gilmer, and Dauros are gonna be subbed as "Bomb-Burst", "Submarauder", and "Skullgrin". Though they said that some like Ginrai and Minerva (who do have Western counterparts) will be keeping their Japanese names, but there's no telling where they'll draw the line with the others.

Though, I'm not even sure they're gonna even get Ginrai's names right. In the slideshow, super Ginrai was called "God Ginrai" and the real God Ginrai was called "Super God Ginrai".


And they're renaming the Godmasters as being "Powermasters", which is an entirely different concept whose only similarity lies within aesthetics rather than function. #-o
For Victory, Deszaras is using his "Deathsaurus" name, which is still irksome considering how he's not even a dragon or dinosaur! He's a bird kaiju!
And then there's the Breastforce. *facepalm* Since they're too paranoid to use this term, they've crafted a cover up term in the form of "Chestforce".

As you can see, I am very disappointed in this. Regardless of the flaws of Metrodome's and Madman's DVDs, or even those of the TV-nihon fansubs, at least they tried to adhere to artistic authenticity (TV-Nihon especially). This, however, is just sad.
