Currently, it's impossible to create an Index with the same definition (same keys) but a different partial than one that already exists in the collection.
Trying to do it, produces the following error:
The full response is

{
	"ok" : 0.0,
	"errmsg" : "Index: {
		v: 2,
		key: {
			prop: 1,
			timestamp: -1
		},
		name: \"name1.prop\",
		ns: \"db1.col1\",
		partialFilterExpression: {
			name: \"name1\"
		}
	}
	already exists with different options: {
		v: 2,
		key: {
			prop: 1,
			timestamp: -1
		},
		name: \"name2.prop\",
		ns: \"db1.col1\",
		partialFilterExpression: {
			name: \"name2\"
		}
	}",
	"code" : 85,
	"codeName" : "IndexOptionsConflict"
}

My indexes are "dynamic", i.e. they will be added to the collection as Documents are added to another collection. Being so, I need to later add these indexes, but this bug won't allow me so.
Now, the only option is to make the index not partial, but I don't really like that, since it would probably use some unnecessary space.