Hello
Regarding this ticket, which is now closed, it appears that the issue still exists with the latest version of the MainWP Child plugin.
https://newcom.mainwp.com/t/boilerplate-posts-being-duplicated/1173
Are you able to try the MainWP 4.1 beta version and see if that solves the problem?
I tested the latest Beta and the issue has been resolved. Thanks…
Thanks for letting us know.