How to update user-defined roles in MongoDB 3.0 in a sharding environment?

Question

I'm using MMS to manage my a typical sharding cluster with just one shard (at the moment): 3 mongod for shard000 (2 servers + 1 arbiter) + 1 config server + 2 mongos instances.

Auth is enabled and it's working well. I've added a user-defined role in the MMS admin console, and I can see it in mongo shell.

db.system.roles.findOne()
{
    "_id" : "admin.myrole",
    "role" : "myrole",
    "db" : "admin",
    "privileges" : [
        {
            "resource" : {
                "db" : "",
                "collection" : ""
            },
            "actions" : [
                "changeCustomData",
                "changePassword",
 ...

I want to change it to AnyAction on AnyResource (as doEval action requires). So, I'm trying to execute this:

db.runCommand({ "updateRole": "myrole", "privileges": [  { resource: { anyResource: true}, actions: [ "anyAction" ] } ] }); db.system.roles.findOne()`
and for one second, I get the result I want:
{
    "_id" : "admin.myrole",
    "role" : "myrole",
    "db" : "admin",
    "privileges" : [
        {
            "resource" : {
                "anyResource" : true
            },
            "actions" : [
                "anyAction"
            ]
        }
    ],
    "roles" : [ ]
}

But, about two seconds later: the role got restored:

configsvr> db.system.roles.findOne()
{
    "_id" : "admin.myrole",
    "role" : "myrole",
    "db" : "admin",
    "privileges" : [
        {
            "resource" : {
                "db" : "",
                "collection" : ""
            },
            "actions" : [
                "changeCustomData",
                "changePassword",

...

and I don't know "who" is restoring it. I've tried the above commands from the PRIMARY and from CONFIG server in admin database.

How can I get the role stored?

P.S: I know that "eval" is deprecated in 3.0, but what I'm asking is the reason I can't update the role.