Timestamp isn't resolved in deep update paths

[texels]

When I try to put a timestamp ( via firebase's TIMESTAMP or { '.sv : 'timestamp' } object, deep objects are not resolved to the time:

Test
`
const Mock = require( 'firebase-mock' )
const { expect } = require( 'chai' )

let database = new Mock.MockFirebase()
const firebase = Mock.MockFirebaseSdk( ( path ) => {
return path ? database.child( path ) : database;
} )

const time = 10
Mock.MockFirebase.setClock( () => time )

describe( 'Firebase Mock Timestamp', () => {
beforeEach( () => {
database = new Mock.MockFirebase( null, null )
database.autoFlush( 1 )
} )

it( 'should set all timestamps', async () => {
const ts = { '.sv' : 'timestamp' }
await firebase.initializeApp().database().ref().update( { t : ts, t2 : ts, 'd/e' : ts, 'x/y/z/aa' : ts, 'a/b/c' : ts } )
// await firebase.initializeApp().database().ref().update( { "t" : { '.sv' : 'timestamp' }, "a/b/c" : { '.sv' : 'timestamp' } })
const data = database.getData()
console.log( JSON.stringify( data, null, 2 ) )
expect( data.t ).to.equal( 10 )
expect( data.t2 ).to.equal( 10 )
expect( data.d.e ).to.equal( 10 )
expect( data.x.y.z.aa ).to.equal( 10 )
expect( data.a.b.c ).to.equal( 10 )
} )
} )`

the resulting console log shows:
{ "a": { "b": { "c": { ".sv": "timestamp" } } }, "d": { "e": 10 }, "t": 10, "t2": 10, "x": { "y": { "z": { "aa": { ".sv": "timestamp" } } } } }
Expected
the a/b/c and x/y/z/aa should both be 10, and not the timestamp object