Is it required that a capacitor is marked X2?
If the Wima MP 3 is this one (or similar): -

And it has &quot;X2&quot; written on it... then for the sake of peace of mind, choose a capacitor that is also rated as &quot;X2&quot; or better.
I don't see &quot;X2&quot; in the data sheet for the MKT1822 device so, dig a little deeper and find one that you are confident about.