For a comprehensive list of other examples of issues with 2D planes in models not being mirrored as expected, click here.
The bug
The planes composing dripleaf plants do not mirror on the back as one would expect, resulting in physical/illogical weirdness.
How to reproduce
Place a small dripleaf
View a specific leaf of the block from above
View the exact same section of that leaf from below
Note that the exact texture pattern at that position is different, even though it should be the same
Relates to MC-190774, MC-199237, MC-199239, MC-199241, MC-199242, MC-199248, MC-201748, MC-201750, MC-201751, MC-201753, MC-201760, MC-202595, MC-202598, MC-203036, MC-205158, MC-206570, MC-212305, MC-214693, MC-214694, MC-214695
Can confirm.