Rear derailleur not in line with cassette

Question

I have just installed a new rear derailleur (Shimano Acera - RD-M360-SGS), and I feel like that the pulley has a weird angle (image below). It does shift but not sure if it's healthy. Any idea what could've gone wrong? Is it just a faulty item?
Edit (reason for installing new derailleur):
The derailleur hanger got bent, shifted down to 1 on the way home and the derailleur got pushed into the spokes: derailleur was beyond repair, but spokes survived. My local shop straightened out the hanger for me

Argenti Apparatus · Accepted Answer

Often a bent derailleur will kick the bottom of the cage inwards. In your case the derailleur is twisted around the vertical axis so the 'front' edge of the cage is pointing outwards.
The first thing I'd check is that you do not have the mounting bolt cross-threaded.
I'd also take the derailleur of the frame and check that that it is not bent.
The hanger may not have been properly straightened, and it might still have a  vertical axis twist. Did the shop use a proper hanger alignment tool? Using a proper tool with ensure the threaded bolt hold is parallel to the wheel axle.

Т. Сергей · Answer

Maybe the derailleur shaft (axle, pivot)  or hook (the frame's hanger for the derailleur) is curved.
It is not healthy for the chain rollers and will increase wear over time.

Michael · Answer

Looks bent but could be optical distortion from the camera. Did you watch the mechanic bend back the derailleur hanger? They should use a special derailleur hanger alignment tool which makes sure it’s straight, not just eyeball it. It would be very unusual for a new derailleur to come bent out of a sealed box.

Answered by Michael on April 18, 2021

MaplePanda · Answer

Some modern derailleurs indeed come purposefully bent from the factory, but yours doesn’t look right. I think your hanger is bent inwards, but it’s hard to guarantee that from a photo.
Try removing the hanger and placing it on a flat surface, like a piece of glass or something. Shine a light from one side and see if you can see light peeking out from underneath, indicating a bend.

Rear derailleur not in line with cassette

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