No, adding "Meiryo" to the pref does not fix bug 1703084 completely in non-100% DPI displays.
Bug 1867381 Comment 4 Edit History
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No, adding "Meiryo" to the pref does not fix bug 1703084 completely in non-100% DPI displays. And I don't think the underline offset of Meiryo is bad. So, doing this only for specific web page must be wrong approach.