I get nill raycasting at some origins these origins appear to be on an 8 stud grid, I would suspect a BSP tree, or Quadtree is to blame for this behavior,
reproducible example, uncopylocked:
Workaround:
-Removed, check above
Have some players working on finding patterns in the sticking, hopefully they return some useful information, and something I forgot to add in the post, the unit itself is in the ignore list, and the ray does pass thru the unit, before reaching the ground, perhaps its related to the ignore code? what does the raycast code look like? is it a dot product to the face of all the bricks, or is it an orthogonal projection of Workspace to the raycast’s Vector? this will be useful to know, since a projection would do per face culling, where a dot product like method is less likely to do culling
got a reproducible example, attaching it to my post. Mods please read, this is a more serious glitch than I had first thought
I encountered something like this a long time ago.
I had four parts equally spaced. One part just would not get recognized though. I could raycast from it and find an object, but if I raycasted back from said object it wouldn’t find the origin.
I spent a long time narrowing down possibilities, and making a minimalistic example, in my case, it seems position 0,32,0 is a deadzone for raycasting, nothing is definite but that position, which is weird
Srsly mods, I’m getting downvotes and complaints from this, please fix it 
gotten 5 downvotes because of this so far, and we have been keeping 13-1 ratio pretty strongly, which is pretty nigh lost now because of all the recent downvotes, 5 downvotes can be really be devestating when you are a new game just starting out, We have been on the top rated military for a long time, now, we are dropping off of it 
please guys, I need a fix, or at least recognition that this is being worked on, so I can give my user base an update on this glitch