Cannot open a READ_WRITE connection after a READ_ONLY connection even if it is closed

I might be doing something wrong here, but I'm wanting to use both READ_ONLY connections and READ_WRITE connections and even though it works most of the time there are cases where a READ_ONLY connection is ran first and once that happens any subsequent READ_WRITE connections fail to be created.

This is using Promises and async/await so I'm specifically waiting for connections to close before opening new connections as I know you can only have one READ_WRITE connection at a time.

Here is a Gist for example: https://gist.github.com/Rosslington/9aecbb3eb51386cd684cc6e538bfcfb9