The original goal of MS Word was to duplicate the output of a typewriter. Fonts, spacing, tab stops, points, etc. were standardized, and faithfully duplicated by MS, as far as they could. Lesser used symbols and styles, such as a superscript "th", would be less likely to match up. Unsurprisingly, it is the "th" that matches Word's output the least.
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|...............| We live in the nick of times.
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