The event handler responsible for adding EAP to devstudio runtime locations gets called immediately after the main installation, no matter what state devstudio is in. Hence, EAP is not usually added to runtime_locations.properties.

On windows, runtime detection can still somehow get past this and finds EAP on its own. But on mac it doesn't. Plus the location of runtime_locations.properties file on mac is different to other platforms (needs update in the code).
And btw. it could use some logging as well.