Milo said that Bannon was known for fits of anger - but they are to be taken with a grain of salt. Milo also said something like “I know who my Daddy is [Trump], but also don’t think I need to take sides.”
I’m guessing that Bannon and Trump didn’t see eye-to-eye on everything. Who does? And then get some liberal writer to skew things. And I don’t think the Trump kids are all that much anyway, which is where some of this disagreement is coming from.
The Bannon flare up is bring the mainstream establishment GOPers, who really hate Trump’s support of an economic nationalist agenda, out of the woodwork.