Unable to flash from file using USB drive on EtcherPro

Hi,

I am trying to use a USB stick with our .img files on it to flash multiple SD cards using the Etcher Pro.
The USB stick is not being recognized as a source in slot 1. It flashes for a second when plugged in and then doesnt seem to be doing anything. The Etcher pro light for port 1 stays off.

If the same USB stick is plugged into other ports, it recognizes it as a target and the Etcher Pro light for that port turns white.

I have tried formatting the USB stick as different formats. exFAT, FAT-32, ext4 and they all have the same above results.

I have tried with our image uncompressed (~8GB) and compressed as .gz (~1.2GB).
I have tried with freshly formatted drives with nothing on them.

The formatting and file transfer is happening from a Mac if that matters.
I did try deleting the hidden Mac specific files.

Nothing seems to allow it to read the drive in the first slot as a source.

I remember being able to use a USB drive as source when I first got it, so guessing some software update broke this feature.

It is running 1.14.3 it seems from the settings menu.

Any help is greatly appreciated!