B4X:
{
"monetaryValue": {
"value": 100.0,
"value": "ONE HUNDRED"
}
}
This is valid JSON according to https://jsonformatter.org/ and the RFC supports this saying "The names within an object SHOULD be unique" rather than "The names within an object MUST be unique".
This doesn't actually cause a crash but obviously as a Map is used you only get one value rather than two. Unfortunately in my case the wrong one.