i often find its after the fisrt infill that people have problems.
When its a new set they treat them like gems as they are all new and they are not used to them so they're careful. then after 2/3 weeks they just think 'well i'm used to them now' and suddenly the care has gone.
like you said,
*its only on one hand,
*four fingers in a row,
*the other nails are not lifting:
She has most definatly knocked them!!