Inconsistent use of the em dash (—) spacing rules

[Rongway]

At least in the examples you provided, the spaceless em dashes are those used to provide a clarification, amplification, or digression. When they instead represent a complete interruption, there is a space after. When using an em dash to represent a complete interruption, a space can be added after the em dash to represent a slightly longer pause than just the em dash on its own. This rule of em dash spacing is probably not mentioned in your style guide because scholarly writing does not typically allow for complete interruptions to thoughts the way that natural dialog does.

Unless there are examples where there are spaces after an em dash that supplements rather than interrupts, I would call everything fine.