Inconsistent results with Meteor's pub/sub feature - mongodb

Question

I'm experiencing inconsistent results with Meteor's pub/sub feature, and I suspect it's a source of confusion for a lot of developers hitting the threshold of an MVP built in Meteor becoming a production app.
Maybe this is a limitation of MergeBox:
Let's say I have a collection called Events, in which I have document-oriented structures, ie, nested Array, Objects. An Events document might look like so:
// an Events document //
{
_id: 'abc',
name: 'Some Event',
participation: {
'userOneId': {
games: {
'gameOneId': {
score: 100,
bonus: 10
}
},
{
'gameTwoId': : {
score: 100,
bonus: 10
}
}
}
},
'userTwoId': {
games: {
'gameOneId': {
score: 70,
bonus: 15
}
},
contests: {
'contestOneId': [2, 3, 6, 7, 4],
'contestTwoId': [9, 3, 7, 2, 1],
}
}
},
}
}
So at these events, users can optionally participate in games of certain types and contests of certain types.
Now, I want to restrict subscriptions to the Events collection based on the user (show only this user's participation), and, sometimes I'm only interested in changes to one subset of the data (like, show only the user's scores on 'gameOneId').
So I've created a publication like so:
Meteor.publish("events.participant", function(eventId, userId) {
if(!Meteor.users.findOne({_id: this.userId})) return this.ready();
check(eventId, String);
check(userId, String);
const includeFields = {
name: 1,
[`participation.${userId}`]: 1
};
return Events.find({_id: eventId}, {fields: includeFields});
});
This publication seems to work fine on the client if I do:
// in onCreated of events template //
template.autorun(function() {
const
eventId = FlowRouter.getParam('id'),
userId = Meteor.userId(),
subscription = template.subscribe('events.participant', eventId, userId);
if (subscription.ready()) {
const event = Events.findOne({_id: eventId}, parseIncludeFields(['name', `participation.${userId}`]));
template.props.event.set(event);
}
});
Happily, I can use the Event document returned that includes only the name field and all of the user's participation data.
But, later, in another template if I do:
// in onCreated of games template //
template.autorun(function() {
const
eventId = FlowRouter.getParam('id')
gameId = FlowRouter.getParam('gameId'),
userId = Meteor.userId(),
subscription = template.subscribe('events.participant', eventId, userId);
if(subscription.ready()) {
const event = Events.findOne({_id: eventId}, {fields: {[`participation.${userId}.games.${gameId}`]: 1}});
template.props.event.set(event);
}
});
I sometimes get back the data at event.participation[userId].games[gameId], and sometimes I don't - the Object that's suppose to be at gameId is non-existent, even the it exists in the Mongo document, and the subscription should include it. Why?
The only difference is between the two calls to Events.findOne() is that in the latter, I'm not requesting the name field. But, if this is a problem, why?. If minimongo already has the document, who cares if I request parts of it?
The subscriptions in both templates are identical - I'm doing this because the games template is available at a route, so the user could go straight to the games url, by-passing the events template altogether, so I want to be sure the client has the document it needs to render correctly.
The only way I've gotten around this is to make a straight Meteor method call to the server in the games template to fetch the subset of interest, but this seems like a cop-out.
If you've read this far, you're a champ!