Upvoted and non-upvoted comments on Mi Yodeya Meta look the same to me on mobile. For example, the following screenshot shows three comments: one by the person who took the screenshot, one he had upvoted, and one he had not; the latter two have the same-looking voting arrow.
User-Agent: Mozilla/5.0 (Linux; Android 9; Mi A1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.99 Mobile Safari/537.36