Mich. Comp. Laws § 500.5244: Liability for payment under invalid law or ordinance.

Sec. 5244.

No personal liability shall arise against any director, trustee, officer, or agent of any insurer by reason of any payment made by or on behalf of such insurer on account of any taxes, licenses, or fees paid pursuant to any statute, law, or ordinance, even though the statute, law, or ordinance is subsequently declared or held to be invalid.