Rotation in Gimp 2.10 is blurrier than in Gimp 2.8

Hello,

GIMP version: 2.10.4

Operating System: Ubuntu 16.04 & Ubuntu 18.04

Package:

• AppImage from https://github.com/aferrero2707/gimp-appimage/releases for 16.04
• otto's ppa for 18.04 https://launchpad.net/~otto-kesselgulasch/+archive/ubuntu/gimp

( I know flatpak and snap exist but in both case I couldn't manage to set Gimp in French language )

Description of the bug

the resulting image after a rotation in Gimp 2.10 is more blurry than in Gimp 2.8

Please describe your issue with details.

https://postimg.cc/gallery/lam6hqbe/

• files containing _28 in their name come from Gimp 2.8
• files containing _2 in their name are successive rotations ( take a file, apply a rotation, save that file, exit. Then open that saved file, apply a rotation, save, exit. Then take this saved file… )

Comparison between two resulting images ( even with the gif ugliness, difference can be seen ) https://pix.tdct.org/upload/original/1532799388.gif

Discussion about that issue ( in french ) : https://forum.ubuntu-fr.org/viewtopic.php?pid=21947544#p21947544

Reproduction

Is the bug reproducible? Always

Reproduction steps:

1. open same image in Gimp 2.8 and 2.10
2. apply same rotation. Save in tif or png.
3. compare the 2

…

Expected result: better or at least same quality

Actual result: lower quality in 2.10