Guild Wars 2

Does anyone know whether you lose your agony infusions in your accessories when you attune it?

You lose your infusions and your legendary weapon (if you have one). Cause they need the legendary (or exo for lack of) to make the attunement align properly.

Ask any Asura.

You can buy an extractor inside of Fractals on the second island to take out current infusions before you Infuse/Attune.