includeUnknown not working as expected

[Devmacs]

I didn't test what SymSpell would return in this case, but this output doesn't seem right to me :

spellchecker.checkSpelling('eradicate', {
    includeUnknown: true,
    maxEditDistance: 4,
    verbosity: 1,
    includeSelf: false
});
// lastResults.length === 1, lastResults[0] --> 'eradicate'

Shouldn't includeSelf: false with includeUnknown: true return no results in this case? 'eradicate' is in the dictionary, so it isn't an unknown. As per Wolf's comment in another issue :

With includeUnknown=true input terms not contained in the dictionary, and with no suggestions in the dictionary within the maximum edit distance will be still included in the output.

Or did I misunderstand his explanation?