Broken OTF fonts on Windows 10

Has anyone else experienced broken OTF fonts with Wordpad on Windows 10? I’m having trouble with a font that has extensive language coverage; Underware’s latin plus, and pinyin, and Vietnamese. The font works fine as a Truetype font; only CFF files are broken.

With an OTF font some accented letters, and adjacent letters, will fall back to system fonts. For example, I’ve been testing the font with the Windows Vietnamese keyboard layout. This is wacky. I can input â but ẩ (adding a hook) will fall back to a system font. What’s weirder is that if â but ẩ are adjacent the first â will also fall back when the hook is added to the second â. A list of all the glyphs in the font will turn into a mess of letters falling back and taking adjacent letters with them,

So far I’ve tried comparing CMAP and OS/2 tables and found no differences other than the SFNT version. I’ve also tried dumping and recompiling with TTX and adding the TTF files’ DSIG with OTMaster. Nothing fixes it.

Has anyone else had this problem? Does anyone have suggestions?

I had a look at it and it seems to be a bug in WordPad. I’m trying to install Office on my virtual machine right now…
Edit: Office is finally up and running and your font works fine in Office (and Notepad). So from what I can tell, WordPad is broken.