Issue with changing the font syle of the first character

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In MathLive, type "H-C", select "H" with the mouse, open Menu and select Font Style -> Roman Upright, then select "C" with the mouse, open Menu and select Font Style -> Roman Upright. The expected LaTeX result is \mathrm{H}-\mathrm{C}. The actual result is H-\mathrm{C}.

Note that H is displayed roman upright inside MathLive, but the generated LaTeX code does not match the display inside MathLive.

Is there a workaround?