Outlet Box - near a butt joint (old and new sheetrock).
Butt joint is good.
In widening this area where the outlet is, skimming and feathering wide expanding the butt joint - floating more mud around the outlet box area to flatten things out with Green Bucket mud.
Noticed a air pocket in the sheetrock. Took a screwdriver and decided to pry the pocket. The skimmed JC that was feathered thin seemed to be easily come off with the screwdriver....
I ended up removing the loose area, and used ES hot mud instead. We'll see how she looks tomorrow.
this sounds to me like 1 of 2 things? either you were sanding between coats? leaving dust behind. or the mud wasn't mixed properly? air pockets in the mud? personally, having done drywall nearly 30 years. I always peeled the plastic cover off the top and poured about a quart of water on top, then mixed it thoroughly. using a 1/2"drill and mixer until having the consistency close to that of peanut butter. never sanding between coats, never had this problem. or possibly the mud froze between second and final coat? I have once came across bad drywall where the paper wasn't glued to the gypsum properly. couldn't tell until painted, the paint caused all the glued paper to separate from the gypsum. had to redo it, adding second layer of drywall, then extend all doors and windows jambs. the hot fix may work? but sounds like dust or air to me