Noto font not working in Acrobat, works fine in PDF-XChange Editor

Originally posted here. Based on a reply to that, I believe this is the correct place to post. If it is not, please tell me where to post.

We create PDF files in our library (our own home-grown solution).

Using the Noto fonts for CJK glyphs, the PDF we create displays fine in PDF-XChange Editor but in Acrobat we get a warning dialog and then two of the lines don't display. File: ATE-3106.pdf

I've tried to figure out what we have wrong, but I haven't been in our PDF code in years and so I'm finding I'm not remembering much. What is incorrect in what we're writing? We're encoding using identity-h.

thanks - dave