Yes, Russia has specifically threatened to use the withdrawal clause if the US does missile defense. Russian statement:
“The Treaty between the Russian Federation and the United States of America on the Reduction and Limitation of Strategic Offensive Arms signed in Prague on April 8, 2010, can operate and be viable only if the United States of America refrains from developing its missile defence capabilities quantitatively or qualitatively.
Consequently, the exceptional circumstances referred to in Article 14 of the Treaty include increasing the capabilities of the United States of Americas missile defence system in such a way that threatens the potential of the strategic nuclear forces of the Russian Federation.
Why is it good for the USA to agree not to allow converting missile launchers to interceptors, and why did all those ex-Bush security characters say this is such a good deal?