Word for Mac style linking behaviour

I've been at war again with Word for Mac for a while now. I don't remember coming across this particular issue before.
The issue seems to occur with weights above weightclass 400.

Here's the issue:

1. I'm selecting the Black weight from the font menu. That goes well, but I notice it activates the Bold button, even though this weight is not style linked as Bold of another weight. It is only style linked with Black Italic.
   
   
2. Then I'm enabling the Italic button, but this gives not the desired result. It shows a fallback font.
   
   
3. If I disable the Bold button after that it shows the correct Black Italic style

I've seen this happening also in several other font families from other foundries. For instance to the UltraBlack weight of Adobe's Acumin Pro SemiCondensed family, but strangely enough not to the same weight in the Acumin Pro normal width family.

I've been editing the nametables in various ways to see if there's anything there that could solve it, also the fsSelection settings, but to no luck.

Does anyone have experience with this issue?