gparted f2fs moved/resized partition mount fails, despite OK fsck.f2fs result

[rjmaris]

Introductory remarks:

• I'm a bit wondering why a f2fs partition that's shifted some GiB to the right is no longer mountable ("mount(2) system call failed: Structure needs cleaning"), despite fsck.f2fs giving no errors but the following remark: checkpoint state = 181 : trimmed nat_bits unmount
• My experience is not unique. Here is a link to someone's reported comparable problem: https://beroal.livejournal.com/80945.html

I post this issue because it seems that the behaviour is related to f2fs-tools.

After having tried testdisk tools (specifically: photorec - which recovered only a part of the files) I gave ddrescue a try.
No changes/error corrections to the partition are executed.
Then I found this sourceforge entry, where a patch to f2fs-tools 1.14 is successfully tested and which fixed "wrong sit/nat bitmap during rebuild_checkpoint()". Therefore I cloned this repository and built v1.15, where this patch is included. No file system changes result in applying this version or even g-dev-test branch.
The attached transcript contains a final execution of fsck.f2fs, which is based on f2fs-tools 1.14, but using 1.15 the result is the same.

ddrescue-transcript.txt