The TPS gap fillers that were removed from the undersdie of the
orbiter were both located at intersections where there were new tiles
installed. I could tell since new tiles are very black in color,
lacking the overcoat of contaminants that are seen on older tiles. When
one filler was removed, I could se the red RTV adhesive used to glue it
in place, and it seemed to look unevenly applied.

My guess is that some KSC tile technician(s) did a poor job
installing the gap fillers to begin with. Not enough adhesive could
cause it to come loose and protrude out.

Matthew Ota

Not a spacecraft engineer, but I did stay at the Holiday Inn