Closely relates to MC-250075.

The bug

The leaves planes used for bamboo range from 0.8 to 15.2 instead of 0 to 16. This implies that they were taken from a cross model and the rotation removed without remembering to also change the model element range, which is also what caused MC-250075.

How to fix

Easy fix - just change the "0.8" and "15.2" instances in models/block/bamboo_small_leaves.json and models/block/bamboo_large_leaves.json to "0" and "16", respectively. Model files that apply this simple fix are attached, which Mojang are obviously free to use.