Missing parameters on SchemaType

[simllll]

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

What is the current behavior?

error TS2339: Property 'instance' does not exist on type 'SchemaType'.
error TS2339: Property 'options' does not exist on type 'SchemaType'.
error TS2339: Property 'schema' does not exist on type 'SchemaType'.

If the current behavior is a bug, please provide the steps to reproduce.
According to the documentation and in preivous versions this was working, by accesing .instance .optoins or .schema of a SchemaType, e.g. by
Model.schema.path(schemaPath).instance;SchemaType
see also https://mongoosejs.com/docs/schematypes.html

What is the expected behavior?
Add type def for instance, options and schema.

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
mongoose 6.0.0