-webkit-text-orientation: upright is ignored if font-feature-settings is set and if the font is YuMincho. It looks like both conditions are required to reproduce.
1. Open attached upright-fwid.html
2. See the only last paragraph is sideways
All paragraphs in upright.
Created attachment 270320 [details]
text-orientation: upright with font-feature-settings and YuMincho
Oh, this is because our complex text code path doesn't support stacked latin text. It never did.
Font features just forces you down the complex text code path.