aerator check is just a 'while hes there' thing, not really related to the spurting. after any new tap install you often get bits of flux, little pipe shavings or scale off the old pipework ending up in the aerator mesh. shows up as a weak or splashy flow usually. nothing to do with drinking...
wayners is right it's most likely plasterboard corner tape. quick way to tell, if it flexes easy and the plaster around it feels like dot and dab or stud wall then yeah it's tape, cut it back a few inches past the damage, re-tape with a bit of fibatape or scrim and skim over.
only reason to be a...