The vanilla command block textures have some weird alignment and shading issues:
!Vanilla command block textures
The background pattern of the blocks does not tile properly when blocks are rotated:
!Background pattern on vanilla command block textures
The baked in shading leads to the appearence of light coming from different directions based on the block rotation:
!Shading on vanilla command block textures
This resource pack aims to address some of these issues by updating background texture to tile more evenly, and updating block states to use slightly different panel textures based on face orientation:
!Updated command block texture
!Updated background pattern
!Updated light direction
For another solution that addresses these issues, as well as other issues with panel alignment, check out this 32x32 resource pack or the slim border variant on Modrinth.

