Updates to the vanilla resources and data-driven behaviors are supposed to be versioned by placing any new or altered files into the folder that correspond to the version in which the change is made. However, as of 1.21.120.22 we have discovered that some files in the resource_packs\vanilla_1.21.90\ folder have been changed retroactively. Per (MCPE-228089) this is confirmed to affect the …_mers.tga files in the \textures\paintings\ subfolder, but the extent of the problem could be much greater.
Steps to reproduce
Install the 1.21.101 Hotfix and 1.21.120.22 Preview versions of the game.
Compare all files in the
\resource_packs\vanilla_1.21.90\folder and subfolders for each version.
Expected results
All files should be exactly the same.
Observed results
Some files have changed.
This issue also applies to the fix for (MCPE-217580) wherein the incorrect sun.png file has been retroactively deleted from the
vanilla_1.21.90\textures\environmentinstead of a correct file being added tovanilla_1.21.110\textures\environment\. In that case there is no harm in deleting the incorrect file, but to my knowledge this kind of thing has never been done until very recently, and it is a very risky practice.