Hyphenation of the style is set for 3 letters before, 3 letters after. Correct for the language would be a hyphenation after two letters in this case. Indesign cannot break the word as it wants, INSTEAD it still breaks the word, but inserts no hyphenation. This appears to be a bug. I am attaching a screen shot as well as a package file. The problem is highlighted in yellow on page 26 of the book.

Indesign: 13.0.1
Mac: 10.12.6