Size issue with reimported file

[underwater]

I'm trying to reimport an edited JSON file whose new size is smaller that the original, but the repacker complains that the compressed size is now larger than before:

repack.png

Is that because the new content cannot be compressed as well? Or what's going on here?
(I've attached the original and modified files.)

[underwater]

P.S. I just tried it again, only swapping 4 numbers around, and I'm still getting errors about an increase of the compressed size (even though the uncompressed is identical):

repack2.png