Apparently:
Fabric Conditioner/Softener
There are very good reasons for us saying do NOT use fabric conditioner on wool clothing.
Fabric conditioners were developed to remove static from synthetic fabrics. Synthetic fabrics are solid fibres and cannot absorb anything (which is why they do not “wick”). The fabric conditioner simply coats them to prevent the build up of static and at the same time try to disguise the awful smell that develops on synthetic fabrics, especially those worn next to the skin.
Wool, in contrast, not only does not produce static, it has a core that absorbs moisture. The fabric conditioner will be absorbed into this core, making it impossible for the fibres to do their work of removing the moisture from your skin and releasing it into the atmosphere. Instead it will leave a greasy sticky smelly mess.
If you have accidentally used fabric conditioner on your merino, put it through several cool water rinse & spin cycles to remove the gloop. Then line dry.