Minecraft tries to "locate signs"

Today I was playing in my Creative world. I was flying around.I was randomly clicking in the air and suddenly, a chat message appears and says "Unable to locate sign at (x,y,z coordinates)" This appeared a bunch of times with different coordinates. I pick one of this coordinates, and exactly at that point, there is a sign I placed.
Sorry for the bad grammar and spelling, I don´t know English very well