Missing Myriad Pro Light Vietnamese glyphs

[lhwohl]

I’m working on a Vietnamese document in InDesign, and have no problem using Myriad Pro Regular or a few other weights, but many Vietnamese characters do not appear in the glyphs palette for Myriad Pro Light (characters with specific diacriticals. Anyone know why that’s the case? And oddly enough, the characters seem to work fine in Word. I even bought a clean version, thinking maybe my font was corrupted, but the issue remains even though the glyphs are in the character list on the vendor website (myfonts.com).

[Test Screen Name]

For background information, it is impossible to use Word to check this. Word has a feature where, if a font does not contain a character, it will look through specific fonts on your system to find another font, and will substitute silently. This idea terrifies professional typesetters, so Adobe products never do this. If you are in Windows try the Character Map applet to check included characters.