Is the underside always missing when you go to this location? Also, does hitting it reveal cracks?
are you “sure” its not a sloped block of gleam? based on the screenshot that could be a sloped piece of gleam 
In fact, the texture blending on the walls slightly visible behind the front of the gleam also suggest it’s a slope block…
4 Likes
Stays like this and yes always in the generated area when i dig under
not sloped normal generated