Another workaround, would be to set background-color as the transition property, with a different background color than usual via MT’s transition event value field. Then, set one of the two gradient colors to have zero opacity by dragging the opacity slider down on the color picker. That way the gradient is just one color fading out, instead of blending into a new color. And when the user hovers over the element, the plain background color will transition, creating the effect that the gradient is transitioning.