Tracked properties sometimes throw error when updated #416
Description
Thanks for your work!
js-data.js:6623 Uncaught (in promise) TypeError: Cannot read property 'indexOf' of undefined
version: 3.0.0-rc.5
changed:undefined
changing:true
current:"http://localhost:8000/media/images/blabla/8679ae5a-4f7.jpg"
index:undefined
previous: undefined
this: undefined