When plants are placed by themselves, no shading is applied to them. However, if that very same plant is instead placed inside a flower pot, it suddenly gains shading, which is nonsensical and obviously inconsistent.

Which behaviour is intended is not known, as the evidence is contradictory - the fixing of MC-57159 implies that there not being shading is what is intended, but the resolution of MC-68302 goes directly against that by saying the exact opposite.

As the behaviour in 1.7 and prior was to apply shading to neither, this is what the attached fix pack will do.

This is also a parity issue, as neither are shaded in Bedrock Edition.