Continuity not routing audio properly for calls
FWIW - If I have Settings > General > Accessibility > Call Audio Routing > Set to speaker (nice when using 'Hey Siri' to make a phone call; to have it auto default to speaker phone) My phone and continuity crashes on me.  So I need it set to "Automatic" and it works fine. Took me forever to figure this out.

Not sure if this is applicable to your problem or not but hope it can help you or someone.