Aquinas wrote in Summa Theologiae I-II, q. 94 a. 2:
My question is about quaecumque: whether it is neuter plural accusative and therefore the direct object of apprehendit, or it is feminine singular nominative and linked to quis which probably results in that quaecumque quis altogether means no matter who.illud quod primo cadit in apprehensione, est ens, cuius intellectus includitur in omnibus quaecumque quis apprehendit