Sharing processes is the great strength of Promapp, but we still find that some experts/owners get confused about who can/cannot see processes that are not yet published.
Quite regularly I will get requests for "access" to Promapp which are actually requests for an draft process to be published. Because the user get an "access denied" error, it appears to be about permissions. A more helpful message would be something like "this process has not yet been published so is hidden to avoid confusion. Contact the process expert and/or owner for an update." then list the owner and expert.