Here you go... I have seen this multiple times but I cannot figure it out. I found another under the water that the radar is not detecting... I cannot figure out the commonality.
I have sleepers that radar is not picking up...
Sleepers Min Y will not draw sleepers below that configured height. it is -50 by default in version 5.3.6. you could set it to -200 or so if -50 is too strict.