Just to include my confirmation here, connector 1.5 has indeed fixed my extension issue.
It did seem however to mess with my saved preset configurations, I had to change my configuration back to CRF=19 and I also had to open the Metadata tab on the Export window and disable the sidecar/xmp file creation on every one of my presets (I never had them on before). Unless something else somehow changed all this between yesterday and today, the connector is the only new thing I did. Nothing major there though.
Thanks