Block styles don't work in Post Content block

[tomusborne]

Description

Our block CSS isn't rendered when our blocks appear inside the core Post Content block.

Steps to reproduce

1. Add the core Query Loop (or our Query Loop)
2. Add the core Post Content block inside of it
3. Add a couple of our blocks to one of the posts (a Button, for example)

Expected behavior

The Button should retain its styling inside the loop.

Actual behavior

The styling doesn't exist.

[leohsiang]

Actually post content block works in the core query loop block, as long as there's a post content block outside the GB query loop block, the content format works in GB query loop block.