To reproduce:
1. Open attached Unity project "test.zip"
2. Open "test" scene
3. Click on Canvas --> Text in the Hierarchy window
4. Change Font Style from Normal to Bold
5. Go into Play Mode

Expected result: The fonts should be linked through name reference to other fonts, so changing Font Style from Normal to Bold should trigger the Bold font to be applied instead of regular Editor's bold
Actual result: The linking of the fonts does not work so only the regular bold is applied to the font (see attached gif "LinkingBug.gif")

Reproduced on: 5.5.3p4, 5.6.1p1, 2017.1.0b7, 2017.2.0a1

Note: The user also added another project with the same issue but a different font "fonttest.zip". The bug persists in 5.6.1p1 and 5.5.3p4, but opening it with 2017.1.0b7 or 2017.2.0a1 fixes the bug on every version of Unity