Project background offset in scratch 3 compared to scratch 2

[fsih]

Expected Behavior

Backgrounds should be in the same place

Actual Behavior

Backgrounds load in different places
Scratch 2:

Scratch 3:

Steps to Reproduce

Compare https://scratch.mit.edu/projects/73399968/#editor
to https://preview.scratch.mit.edu/#73399968

Interestingly, 72180668 is a different project which seems to have exactly the same background, and it loads correctly. Maybe comparing these two can provide hints?
https://scratch.mit.edu/projects/72180668/#editor
https://preview.scratch.mit.edu/#72180668

Operating System and Browser

Windows 10 Firefox

[fsih]

@kchadha and I figured out that 72180668's backgrounds have their viewbox and rotation center set correctly (stage size, with rotation center in stage center) while 73399968 has weird rotation centers that are different for the different backdrops (like they might have been generated?)