The source's original version is 1232x1726 JPG. Where' s this PNG version from?

First of all that's certainly is not the actual source, just kiyoe tried to promote his twitter account.

Also If you compare two images, the right side has more content on this one, compared to that 1232x1726 one. The one that was in the reply, though, albeit smaller, does have that part.

However, I don't know where the actual source is.

All I can find is the official news and crunchyroll. But they are all much smaller, not to mention the official site one even has a watermark (but can be easily removed by combining two).

This image, then, apparently was denoised from that 1232x1726 one or similar (it's same as crunchyroll's one but bigger) and someone was crazy enough to add that little bit on the right based on that smaller one (by upscaling first I'd assume).