Sometimes word processors like MS Word [and apparently Excel, too] use "smart" punctuation characters that may look like ordinary ones but are not really. The more obvious example is quotation marks that look like little 6's at the beginnings of quotes and like little 9's at the ends, even though you type them using the same key. Similarly, so-called M-dashes and N-dashes that result from typing two hyphens in a row, depending on whether they have characters or spaces immediately adjacent. They're substituted specialty characters in place of what pressing a keyboard key feeds in. I suspect that's what's happening here -- not a question of the font, but of a "smart" hyphen of some kind.
I haven't dug into this, but you might try exploring in Excel whether there's a setting that will have it use plain ASCII hyphens instead of any specialty variety.
Or look at the actual entity-data text content entry for that Text or Mtext object:
(cdr (assoc 1 (entget (car (entsel "\nSelect Text/Mtext object: ")))))
and it will probably have some special-character-defining code in place of the question marks, which you could replace with plain hyphens using (vl-string-subst).
Or if you can, feed the Excel content to a plain-text editor like Notepad, and read it into AutoCAD from there. That ought to strip any specialness off the hyphens, though I don't guarantee it.
Kent Cooper, AIA