I'm pretty much sure the pronunciation of Duolingo (especially for Korean) is really bad. So you should ignore when it sounds odd, and follow the standard pronunciation. In this case, ㅓ sounds like 'eo', so stick to that.
Same here, and there have been a few like that as well. My wife (Korean) said that several of these are pronounced slightly wrong, so I'll go with your second one and assume the spelling is authoritative instead of the recording.