I had dual insurance for 3 months in 2018. Jan-March. My 1065-B came in 7 days late, so i filed too early. I was covered with my parents during the time. Should i amend?

Dual insurance?  Was one of them obamacare?  Did you answer that you didn't have insurance and have to pay a penalty?

Unless you entered that you did not have insurance and paid a penalty, there is no need to amend your return if you had a 1095B.  The only time there is actually something to report other than "Yes, you had insurance" is if you were covered by Obamacare.  

Thank you!