I won't get all arcane on you, because this is a fascinating issue. Under prior law, patentees had to disclose what is called the "best mode" (the best way to use an invention) for a patent to be valid. So, a competent lawyer had to ask what the best mode was, and had to advise the client to disclose it.
The law changed, and now the best mode must be disclosed but there is no consequence to the client if it is not. Theoretically, though, and even though the patent is not going to be affected at all if the best mode is withheld, the lawyer could be disciplined by the PTO for failing to disclose it. In the real world, though, clients sometimes do not want to disclose the best mode, keeping it a secret to maintain a competitive advantage.
Hence the conflict: perhaps the lawyer will breach a duty but the client will be damaged if the lawyer complies with that duty. I'm not recognizing another issue like this -- where the lawyer's ethical duty could cause the lawyer harm, but leave the client unaffected even though the lawyer is acting in course and scope and a statutory obligation owed by the client is unmet.
And there's more. The new patent act is fun.