TypeError: value.map is not a function for saving settings

[lssweatherhead]

Hello!

Umbraco version: 12.3.3
Preflight version: 12.0.0
Languages installed: just the default en-US

After the initial install this was working okay, but when I try to save the preflight settings it (doesn't do it) and returns this error in the console:

angular.js:15697 TypeError: value.map is not a function
    at preflight.min.js?d=638368770700000000:612:50
    at Array.forEach (<anonymous>)
    at SettingsController.saveSettings (preflight.min.js?d=638368770700000000:606:32)
    at fn (eval at compile (angular.js:16548:15), <anonymous>:4:168)
    at e (angular.js:29123:13)
    at m.$eval (angular.js:19523:16)
    at m.$apply (angular.js:19622:20)
    at HTMLFormElement.<anonymous> (angular.js:29127:13)
    at HTMLFormElement.dispatch (jquery.min.js?d=638368770700000000:2:40035)
    at v.handle (jquery.min.js?d=638368770700000000:2:38006)

It looks like this is happening in the part of the save settings function which is dealing with multipletextbox mapping, specifically this bit:

if (v.view.includes(constants_1.constants.multipletextbox)) {
    for (let [key, value] of Object.entries(v.value)) {
        v.value[key] = value.map(o => o.value).join(','); //here the value is null when it is trying to parse the naughty and nice words plugin
    }
}

This is what it has in the object:

{
    "guid": "1a465035-41d4-44a4-bf64-87ede0cea3be",
    "id": 5,
    "core": true,
    "label": "Nice words",
    "value": {
        "en-US": {
            "value": null
        }
    },
    "description": "These words will be excluded from the readability check",
    "view": "views/propertyeditors/multipletextbox/multipletextbox.html",
    "order": 0,
    "tab": "Naughty and nice",
    "alias": "niceWords",
    "prevalues": null
}

Not sure if I've maybe misconfigured this somewhere, or should be setting the language somewhere?
This seems to fail regardless of whether I have words in the naughty and nice lists or not

Happy to help with a fix if it is not just me missing something!

Cheers,
Laura

[lssweatherhead]

Oh and it also throws a slightly different error if I try to add new words to the naughty/nice lists (the more I write about this issue, the more I am feeling like Father Christmas)

This error, I'm guessing related to the same null issue
angular.js:15697 TypeError: $scope.model.value.push is not a function