We've had this issue for some time now - and are now experiencing additional issues related to CRM users. Any time we add/update a user in CRM, we have to manually force a resync between both environments (actually we don't, Support has to do this for us) for the user to display in Marketo (e.g., when syncing a lead to CRM). Furthermore, if an existing user in CRM is updated - e.g., their email address changes (which happens when a contractor transitions to an FTE in our organization) - the resync will now create two entries in Marketo; and Marketo will generate an error when trying to sync a lead to CRM, assigned to this user - since there is more than one user (or so Marketo thinks). Is this happening to any of you that use Dynamics CRM? We're on Dynamics 2016 online (with version 188.8.131.52 of the Marketo solution installed in CRM).