$dontVersionable works only in SNAPSHOT mode

[robsonek]

Why don't you remove fields from $dontVersionable in DIFF mode like in SNAPSHOT mode?

public function getVersionableAttributes(array $replacements = []): array
{
    return match ($this->getVersionStrategy()) {
        VersionStrategy::DIFF => $this->getDiffAttributes($replacements),
        VersionStrategy::SNAPSHOT => $this->getSnapshotAttributes($replacements),
    };
}

protected function getDiffAttributes(array $replacements = []): array
{
    return array_merge($this->getDirty(), $replacements);
}

protected function getSnapshotAttributes(array $replacements = []): array
{
    $versionable = $this->getVersionable();
    $dontVersionable = $this->getDontVersionable();

    $attributes = count($versionable) > 0 ? $this->only($versionable) : $this->attributesToArray();

    return Arr::except(array_merge($attributes, $replacements), $dontVersionable);
}

[overtrue]

It seems like a bug, I've fixed it in 059d042