I doubt this will conflict will arise this summer, but in theory it could.
My day job is in a law firm, where there is a duty of confidentiality to clients, some of whom may be reporting domestic violence situations where there may also potentially be abuse to the children.
My side job is teaching, where as a result I am a mandated reporter and obligated by law to report any reasonable suspicions of child abuse. See Cal. Pen. Code Sec. 11165-66.
This likely won't become an issue for me because it's a big metropolitan area, and the families I'll be teaching are much wealthier than the firm's clients, but I do wonder what would happen if a kid I teach comes from a client family where as a result of the representation I would have knowledge of potential abuse.
The law seems to limit knowledge to that acquired within the scope of the employment, but if I'd had external knowledge to raise my suspicions, it would be much easier to "know" as a result of my teaching interaction about the possibility of abuse.
Some guidance may come from Sec. 11166.3(a)(1), which does seem to exempt clergy who who find themselves in a similar situation from their mandated reporter obligations ("A clergy member who acquires knowledge or a reasonable suspicion of child abuse or neglect during a penitential communication is not subject to subdivision (a)."). However doctors, who also have confidentiality obligations, are not exempted from mandated reporter obligations.
The statute, as far as I can tell, also makes little mention of attorneys, apart from district attorneys and attorneys representing the affected child (Sec. 11165.7(a)(18)), so there is little guidance there. Nor could I find any cases on the subject.
Should the matter arise, I think a strong case can be made that attorneys who acquired their initial suspicions through their attorney work should be exempted like clergy are, but I can't find direct support affirming this analysis. Which seems like a significant problem. It's not that I think there are so many attorney-swim instructors walking around, but there are many other types of teaching opportunities professional adults can pursue. Maybe an after-school model rocketry club, for example. Surely we would like to encourage all interested and qualified adults to get involved with teaching children in the community, and surely we would want to include attorneys in those ranks.
Volunteers are excepted from the mandated reporter requirements (Sec. 11165(b)), but it hardly seems a good solution to require lawyers to teach for free in order to avoid the conflict. Not every attorney earns enough where foregoing even a nominal payment for their labors is so easily affordable.
I suppose the question is academic until such a situation should happen to arise, but given that "[a]ny mandated reporter who fails to report an incident of known or reasonably suspected child abuse or neglect as required by this section is guilty of a misdemeanor punishable by up to six months confinement in a county jail or by a fine of one thousand dollars ($1,000) or by both that imprisonment and fine" (Sec. 11166(b)) it seems like an important one to resolve.