Directory Origin producing field names enclosed in 'single quotes'?!

edit

Counter intuitively, I found the solution to my problem was to remove the leading '/' from each fieldPath value in the Field Path To RegEx Group Mapping JSON configuration.

This is despite the default template suggestion starting with a '/'!

Ugh.

So in Field Path To RegEx Group Mapping I had:

[
    {
        "fieldPath": "/date",
        "group": 1
    },
    {
        "fieldPath": "/time",
        "group": 2
    }, 
    ...
]

Whereas, I needed to have:

[
    {
        "fieldPath": "date",
        "group": 1
    },
    {
        "fieldPath": "time",
        "group": 2
    }, 
    ...
]