He indicated that there was an issue with PPM that broke installations.

Thats vague, but AFAIK (and I'd like to think I know), there is no issue with core module prerequisites.

Is there an easy way to detect if PPM is installing my module as opposed to CPAN or commandline?

No, however there may be ways to detect if ppm installed your module (perldoc ppm), or rather I should say your distribution.

Should module authors take any action on this topic? If so, what should that action be?

I have a feeling the answer is no.