Poor Acoustic Ceiling Repair
While doing your home inspections, look at the
ceilings and walls very carefully for spots like this. If someone
repairs the ceiling correctly and good enough to where we won't even
notice it, this is a good and a bad thing.
The bad thing is, we won't know why it was originally damaged. If the ceiling patch was done poorly and we don't even notice it, poor repairs give us clues to examine the area above for damage like water leaks. Possibly roof leaks.
The good thing is, the patch or repair that is done correctly looks cosmetically pleasing and will not need to be repaired later.