Here are the ones I took note of in a response a few months ago that may fit what you are asking. Seems to me like “intent” of the person posting the question would be the deciding factor on whether it is sinful or what type of sin it would be.
From Canon Law:
“Can. 209 §1. The Christian faithful, even in their own manner of acting, are always obliged to maintain communion with the Church.
§2. With great diligence they are to fulfill the duties which they owe to the universal Church and the particular church to which they belong according to the prescripts of the law.”
“Can. 211 All the Christian faithful have the duty and right to work so that the divine message of salvation more and more reaches all people in every age and in every land.”
“Can. 212 §1. Conscious of their own responsibility, the Christian faithful are bound to follow with Christian obedience those things which the sacred pastors, inasmuch as they represent Christ, declare as teachers of the faith or establish as rulers of the Church.
“Can. 216 Since they participate in the mission of the Church, all the Christian faithful have the right to promote or sustain apostolic action even by their own undertakings, according to their own state and condition. Nevertheless, no undertaking is to claim the name Catholic without the consent of competent ecclesiastical authority.”
Can. 225 §1. Since, like all the Christian faithful, lay persons are designated by God for the apostolate through baptism and confirmation, they are bound by the general obligation and possess the right as individuals, or joined in associations, to work so that the divine message of salvation is made known and accepted by all persons everywhere in the world. This obligation is even more compelling in those circumstances in which only through them can people hear the gospel and know Christ.”
“Can. 227 The lay Christian faithful have the right to have recognized that freedom which all citizens have in the affairs of the earthly city. When using that same freedom, however, they are to take care that their actions are imbued with the spirit of the gospel and are to heed the doctrine set forth by the magisterium of the Church. In matters of opinion, moreover, they are to avoid setting forth their own opinion as the doctrine of the Church.”