I have plenty of cases/authority that state that contributions can be returned under ERISA 403©(2)/1103©(2) for mistake of fact or because it cannot be deductible under 404.

I am looking for cases/authority where the Plan was sued (or the IRS brought an action against the Plan) for failure to make contributions, and the Plan asserted 403©(2) as an affirmative defense -- claiming they did not have to make the contributions because to do so, would have been a mistake of fact, or that the contributions would not have been deductible under 404 anyway.

Thanks.