Mineshafts still spawning without any support holding them up

The mineshaft 'wood bridges' (not sure what they're actually called) can still sometimes spawn without any wood or chains holding them up as support. This is usually seen at the end of the bridge. View my attached images for a visual representation.

How to reproduce:
Seed: 7953169233438172984
XYZ: 1543 -43 1558