Here's the "deal" with hyphenations:
Kepub and epub are handled differently yet again!
Epub has hyphenations no matter if set to justified or left aligned. But most of them are okay, except for a few unusual words (like the aforementioned souls-cape).
In
kepub there's only hyphenation if the view is set to justified.
That's how it should work for both epub and kepub - no hyphenation when left-aligned, hyphenation only when justified.
Funny thing: hyphenations in kepubs are strange, like elect-ronic, which of course should be like in epubs (use the dictionary) ...