Since W3TC is one of the most used and powerful plugin to enable cashing at every level, I wonder if you found the way to solve this major problem.
I don’t want to switch from that to the more basic plugin “Cache enabler”, since it’s more your side workaround than a real solution as stated here : MainWP child seems not to work with W3 Total Cache Plugin
I would really enjoy using MainWP, but making it easier to setup with most used ones (Wordfence firewall issue and this one now) is somehow a must be. Let’s mention that I never had those problems with ManageWP.
Hoping to read your good involvement here.