Incompatible armor for merc

I recently hired a Moulder Strike, whose attribute is STR, but when I try to put a Garb of the Ephemeral, which is a STR/INT body armor, my merc can't wear it.

As I searched on poe wiki (https://www.poewiki.net/wiki/Mercenary), it says that this merc can wear STR / STR and INT / STR AND DEX gears. Is it a bug, or I am missing something?

Despite the str requirement, the base item is a savant's robe, a int only item.

The base being an int only item doesn't change the fact that the "Garb of the Ephemeral" is a Str+Int Item an with that should be allowed to be worn by an Str Merc. There is no way that this is not a bug.

Fusings are weighted towards blue, not blue and red like a STR/INT chest.

It is an INT chest that also has a STR requirement. Not the same as a STR/INT chest.