Gaps in the floor material-Can't remove the gaps

Hello,

There is a weird gap in the floor that I cannot seem to get rid of. The gap changes as I move the floor up and down as shown in the screenshots attached. When I try to make a new floor, the gaps are still there. What is the cause of this and how would I go about fixing this issue? It has something to do with how close the bridge is to the floor.

EDIT: I now know it is affected by how close the maze between the floors is to the floor. But I am still stuck on how to fix the issue.

Thank you,
Matthew Pepper