I am trying to bulk import via CSV. One of my fields is a custom multi-select field with mapped values. Every line of the CSV that has multiple values for the multi-select field errors with: [ You cannot specify 'None' as an option together with other options ]
The documentation says:

And my CSV looks like this:

I've spent a half a day now trawling Google and these community pages with no luck on a solution. I cannot see a fix unless in frustration I change the field type to a 'labels' type but I'd rather not. Any ideas?