The bug

The acacia trapdoor's texture does not appear to have been updated in the Texture Update, but the acacia door has. As a result, an art style clash can be seen:

• The acacia trapdoor appears to use a duller orange palette, whereas the acacia door has a brighter, more pinkish tone. (Ironically, the acacia trapdoor seems to match acacia planks more than the door does due to this.)
• The acacia trapdoor's shading also appears to be a tad noisier then that of the acacia door.

How to reproduce

1. Place an acacia door
2. Place an acacia trapdoor
3. Compare the textures and art style
4. Repeat with another wood type, such as birch

Expected results

Acacia doors and trapdoors would appear very similar in art style, palette, shading and so on.

Actual results

The discrepancies noted above can be seen.

Further notes

MC-165503 may exaggerate the perceived effects of this issue - it may be advisable to use a custom resource pack to fix it before comparison, or perform the test on barriers or another block which does not impart ambient occlusion.