As I've repeatedly made clear, it's the SM-3s Mk-41 launchers which violate INF. Russia also argues that armed drones are another violation.
Here's a reputable specialist source:
More details on Russia and the INF violation - Blog - Russian strategic nuclear forces
One final point. In response to the non-compliance finding, Russia, of course, made some counter-accusation. What's interesting, these seem to have some merit.
First, Russia says that armed drones qualify as GLCM - a literal reading of the treaty seems to suggest that that's the case. Let me copy part of the discussion over at Armscontrolwonk.com, where Thomas Moore tried to rebuff Russia's claims (not very convincingly, as far as I'm concerned):
The INF treaty defines "ground-launched cruise missile" as follows (Article II.2):
The term "ground-launched cruise missile (GLCM)" means a ground-launched cruise missile that is a weapon-delivery vehicle.
It depends on the definition of cruise missile, but it is provided right there:
The term "cruise missile" means an unmanned, self-propelled vehicle that sustains flight through the use of aerodynamic lift over most of its flight path.
Thomas argued that Russia didn't provide a definition of the term "weapon-delivery vehicle," but it didn't have to - the United States provided one in a note exchange:
In this connection, it is also the position of the Government of the United States of America that the Parties share a common understanding that the term 'weapon-delivery vehicle' in the Treaty means any ground-launched ballistic or cruise missile in the 500 kilometer to 5500 kilometer range that has been flight-tested or deployed to carry or be used as a weapon -- that is, any warhead, mechanism or device, which, when directed against any target, is designed to damage or destroy it.
I don't see how one could make an argument that armed drones are not GLCMs. [UPDATE: Well, maybe there is a way - see the discussion in comments.]
Also, Russia is arguing that deployment of Mk-41 launchers as part of the missile defense sites in Poland and Romania would violate the treaty. This case is not quite clear cut, but Russia seems to have a point.
The Mk-41 Vertical Launch System is capable of launching a range of missiles, including Tomahawk SLCM. There is nothing wrong with that - the INF Treaty does not limit SLCMs and, indeed, allows testing SLCMs from a ground-based launcher as long as this launcher is fixed and located at a designated test site. Unless the United States tested a GLCM from an Mk-41, these launchers are not considered GLCM launchers for the purposes of the INF treaty and, strictly speaking, the treaty does not limit them in any way. But deploying these launchers on land does seem to go against the spirit of the treaty - deployment of a bunch of SLCM launchers on land would be a way to deploy a bunch of GLCMs. And yes, fixed launchers are GLCM launchers in the INF Treaty (Article II.4):
The term "GLCM launcher" means a fixed launcher or a mobile land-based transporter-erector-launcher mechanism for launching a GLCM.
One can argue (as Thomas Moore did) that since the particular launchers that will be deployed in Poland and Romania have not been used to launch SLCMs, they don't qualify as SLCM launchers, but that's not a strong argument. Even though the INF Treaty does not explicitly define SLCM launchers, the common practice in arms control treaties is that if you test a SLCM from a launcher (Mk-41 in this case), all launchers of this type would be considered SLCM launchers. So, I would say that it's reasonable to argue that deployment of Mk-41 anywhere on land outside of agreed test ranges would not be exactly treaty compliant. This would not be an issue if the missile-defense Mk-41 were "distinguishable" from those that were used in SLCM tests, but as I understand, they are not.