There are two things at play here.
First, you need to decide do you want to take the native WordPress approach (just put a link to the media file in the blog post and leave it at that), or take the PowerPress approach (use the Episode Entry Box). The WordPress approach is not podcasting in any sense, it’s just media on a page without any iTunes meta data. This lack of data causes the issues you’re observing because it does not detect all the necessary meta data for the podcast episode media file.
So you are aware, just about all podcasting clients, applications, directories, etc.. observe the iTunes meta data. In other words, to podcast you need the iTunes attributes/meta data set for your podcast.
With PowerPress, you have to tell PowerPress what the media URL is to your podcast episode by using the Podcast Episode Box. PowerPress wlll then detect all the necessary meta data (test with the verify button).
Learn more about podcasting on our podcasting manual: https://create.blubrry.com/manual/