Fails on save when using mongoose 4.x with sub-documents

When I run the following code using node it works as expected however when running it with devtool it return a save error:
`var newOpts = new locator.db.customOptions({
optsType: 'some_opts',
opt1: true,
});`

`var newPerson = new locator.db.person({
name: 'Steve',
customOpts: [newOpts]
});`

newPerson.save(handleSaveResponse) will fail every time when starting my server with devtool but not node