User email being deleted when submitting Profile 2 form i'm debugging a site that I haven't made.  The issue is that the users email address is being deleted. 

I've found which form it's happening on; and by using hook_form_FORM_ID_alter I can see that $form has this information at before sending and not after it's been sent. 

I've written a patch that writes it back in but my question is what the best way is to backtrace where the bug actually is.  I'm using phpstorm as my IDE and have put breakpoints in modules I think could be at fault but without joy.  

Any other tips on this one ?  

Much appreciated.
You will have to check that hook_form_FORM_ID_alter  and the callbacks inside that hook, at least at the end you can check if the $form still have all the previously data