This behavior exists in version 5.7.8
This behavior does not exist in version 5.6.9

Do you want to request a feature or report a bug?

Bug

What is the current behavior?

story is a complex document with many subdocuments and subdocuments arrays
let obj = story.segmentation // this is a subdocument array
let segmentation = {
// json object contains fields according to Segmentation model
}
obj.push(segmentation)

Error output:

Cannot read property ' __$' of undefined\nTypeError: Cannot read property ' __$' of undefined\n at _updateParentPopulated (/Users/avichaishapira/IdeaProjects/bigvu-webserver/node_modules/mongoose/lib/types/documentarray.js:323:14)\n at CoreDocumentArray.push (/Users/avichaishapira/IdeaProjects/bigvu-webserver/node_modules/mongoose/lib/types/documentarray.js:187:5)\n

What is the expected behavior?

array.push is successful

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.

Node v12.10.0
Mongoose v5.7.8
MongoDB v3.3.0