Jiren at the beginning of Chapter 129 fights even more seriously compared to his counterpart who turns on in Chapter 127?

[SIAD]

Jiren at the beginning of Chapter 129 fights even more seriously compared to his counterpart who turns on in Chapter 127?

We can see at the end of Chapter 128, Goku activating the UI Sign for the 3rd time and dodge Jiren's best hits, then UI Sign Goku hits Jiren that hurts a lot. He then starts Chapter 129 and Jiren from the start, matches UI Sign Goku's speed and surpasses Goku in strength. I mean before Goku throws the Kamehameha at him.

Jiren (At the beginning of Chapter 129) was even stronger than before?

 

[Goku9001]

Most definitely. UI Omen Goku was easily able to dodge Jiren's blow and landed one of his own. Afterwards, Jiren battles Goku on a level that is the fastest we've ever seen. They're constantly blitzing around the battlefield emitting explosions everywhere. Jiren is dodging UI Omen Goku and easily overpowers a full powered KHH from UI Omen Goku. UI Omen Goku was nearly defeated until he made his own warcry and powered up again.

Afterwards, Whis claims that Goku is acclimating to Ultra Instinct and getting "deeper", more engrossed into Ultra Instinct where he can fight more autonomously as a result of his "accelerating rise of energy". His reaction speed, attack power. and battle power would naturally improve but Jiren is still keeping up.

Nearing the end of the fight, Jiren pushes UI Omen Goku into a corner by unleashing a flurry of rapid-fire punches that UI Omen Goku could only defend himself against. It's only when UI Omen Goku's proficiency in the form improves once again that he's able to defend against it. In the end, we watch UI Omen Goku's energy rise and envelop the whole arena.

Belmod implores Jiren to finally use his "unstoppable, absolute power" to put an end to UI Omen Goku. Jiren emits an aura as large as UI Omen Goku's when he unleashes his final attack.

Jiren (Absolute Power) ~ UI Omen Goku (Peak) > UI Omen Goku (Deepened Instinct) > UI Omen Goku (Powered Up/War Cry) > UI Omen Goku (Initial) > Jiren (vs. Goku & co.).