Yes, this should apply to weathering over clear coats. Thinned oil paint will attack an enamel coat. While a future coat is pretty tough, it's still possible to damage it with acrylic paint, especially with lots of thinner.
I see from the comment that you use the 'sludge' wash method. You can try just dipping a small amount of paint into the panel line and let capillary action to draw the wash in. Much less clean up to do. This is my preferred method (oil over future) as its gives me more control, but it is more time consuming.