Geminling double buff gems dont work

As the title says, you pick gemling to use gems twice, but when you put in certain buff gems, they do not work/stack.

Some of these gems are: Heightened curse - Vitality - Clarity - Herbalism - precision canibalism.

So pretty much the reason why I took Gemling was because of these gems, but ALL of the games I needed and wanted for my build CANNOT be used twice, eventho the ascendancy says you can.

.