Hey, thanks for the quick update!
My game and video resolutions are both 1280x720 too, so that part checks out.
With the new autocrop, the background is centered, but now there are gaps on both sides—and the bottom still has a bigger gap than the sides.
Without autocrop, it flips: there's a gap only on the right, none on the left, and still that big one at the bottom.
As for plugins, even disabling them doesn’t fix it (I even tested it with a new project, with no modifications), but for reference, I use:
AnimatedBattleBackground.js (1.21)
RMMZ-SpeedDialogue.js
Synrec_TextSounds.js
DotMoveSystem.js
A sprite scaling plugin
A title screen logo plugin
Let me know if you need more info!