Priests can be share in a penitent’s sin during the Sacrament of Confession
“Therefore the priests of the Lord ought, as far as the Spirit and prudence shall suggest, to enjoin salutary and suitable satisfactions, according to the quality of the crimes and the ability of the penitent; lest, if haply they connive at sins, and deal too indulgently with penitents, by enjoining certain very light works for very grievous crimes, they be made partakers of other men ‘s sins.’
Council of Trent
Fourteenth Session, ON THE MOST HOLY SACRAMENTS OF PENANCE AND EXTREME UNCTION
Doctrine on the Sacrament of Penance. CHAPTER VIII. On the necessity and on the fruit of Satisfaction.