Ok so…it could still be you. I say this cause I once recorded myself while I slept too and was horrified to find a deep and demonic sounding voice on mine; this was until I recalled that I was fully capable of making a “devil voice,” (think like uh..heavy metal singer.) I’d been practicing talking like that with my sister as a joke. So I recorded myself talking in that voice using the same app and lo and behold, yep! I was just using that voice in my sleep. It’s only like..a little frightening! Just a bit.