The bug

When 1.8 added doors and 1.13 added trapdoors for other wood types, their textures had colors which matched the color of the wood making them up rather closely. However, the "generic" doors and trapdoors (which later became the oak's type) remained unchanged, which is a problem due to their textures being a tad darker than oak planks. This color deviation is more extreme than any of the other seven wood types.

The Texture Update updated the oak door's texture, but did not resolve this color discrepancy.

How to reproduce

1. Place oak planks
2. Place an oak door next to these oak planks
3. Place an oak trapdoor next to these oak planks
4. Repeat for any or all of the other 7 wood types

Expected results

The oak door and trapdoor would use very similar colors to that of oak planks.

Actual results

Both appear considerably darker.