Thank you for the reply DelphinusVyse.

To clarify, you didn't have any issues with the non-Steam launcher, correct? Only when launching through Steam does this issue occur?

Does this kind of thing happen in other games?

It sounds like this is tied directly to how Steam uses the launcher (the core affinity on one will affect the other). However, I'm not sure how Steam dictates this, nor could I replicate it.

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!