I created a collection for all my Biblical Theology books and generated a bibliography for it. I noticed that some of the entries include "electronic ed." and some don't. It should be consistent, unless there is some rhyme or reason to this, e.g., if the ones with "electronic ed." are ones that are not indexed by page number in the Logos edition so they can't be cited as if they were print-based books. But that doesn't seem to be the case (the Zuck books both have page numbers). So I'd either make it use such a rule consistently (perhaps that would be the ideal, though it would be hard to verify accuracy on this) or always put in "electronic ed." or always leave it out. I personally would probably prefer to have it left out, as the reason I'd be generating these bibliographies would be to pass on to others in which case the "electronic ed." is irrelevant.
I would guess that this is a tagging issue. Most of the "electronic ed." look like older Logos books. Thus I would speculate this represents a shift in philosophy if you need to report in a bibliography that the version your read was electronic. I'm all for striking "electronic ed." from Bibliographies all together.