From my understanding, Jansenism was/is a heresy or are you referring to something else?
In short though… given the extremes some of the Jansenists went to the movement would have certainly played right into the “hands” of someone suffering from scrupulosity.
for proper context one should follow the links:
The papacy struck out against Jansenism in 1653 with the publication of the bull Cum occasione (“With Occasion”) by Innocent X, which condemned five of Jansen’s propositions on the relationship of grace and freedom. The Jansenists acknowledged the heretical tendencies contained in the propositions and the authority of the decision but denied that the propositions in question could be ascribed to Jansen. The general assembly of the French clergy and Pope Alexander VII in 1665 called upon the Jansenists to subscribe to a formula of submission that acknowledged the fact of Jansen’s heretical status. Although Louis XIV was determined to eliminate the Jansenists as a threat to the unity of his kingdom, there was a temporary peace after Clement IX became pope in 1667, and the conflict ceased to be a major concern when the papacy and the French Church clashed on Gallicanism. But after the controversy between the papacy and the monarchy was settled, Louis XIV obtained from Clement XI in 1705 the bull Vineam domini (“Vineyard of the Lord”), which renewed the earlier condemnations, and then in 1713 the bull Unigenitus, which condemned 101 propositions of Quesnel. The promulgation of Unigenitus as French law in 1730 finally caused the decline in strength of the Jansenist party. Organized Jansenism survived only in Holland, where it still exists as a church in Utrecht. It also spread to Italy, where in 1786 the Synod of Pistoia, which was later condemned, propounded extreme Jansenist doctrines.
++ Catholic News Agency: Jansenism
++ Newadvent.org: Jansenius and Jansenism