I have come across the same problem. I tried a few different things to fix it but gave up as just finding and editing the videos was already draining enough for me. Thought I'd just try again later after I finished the pack (I do intend on finishing the Elena Koshka pack one day. It's just not high on my list of priorities right now) Wonder if there is a fix??Already answered in a previous post. When I get the pack fixed, I will post it again.
Handbrake has some kind of issue with unknown sound formats, where it ignores the sound when converting to webms. I didn't make the .mp4s for EO, and don't know why Handbrake can't read the sound off of them.