Cannot publish Entry - "Validation error" - non existing locale?

While trying to publish an entry, the error returned refers to a path that has en-US in it, while I don’t have it activated, I only have one that’s the default: hu.

Is it expected that I’d get en-US in the error report even though it’s not present in the space, or could that be the reason I’m getting the error?

This is the node I have at the given path under the default language in the space (hu, NOT en-US):

{
  "type": "break",
  "position": {
    "start": {
      "line": 1,
      "column": 22,
      "offset": 21
    },
    "end": {
      "line": 2,
      "column": 1,
      "offset": 24
    },
    "indent": [
      1
    ]
  }
}

This is the relevant part of the error report:

"details": "Value must be one of expected values",
"path": [
  "fields",
  "body",
  "en-US",
  "content",
  0,
  "content",
  1
],
"value": {
  "data": {},
  "content": []
},
"expected": [
  {
    "$ref": "#/definitions/Inline"
  },
  {
    "$ref": "#/definitions/Text"
  }
]

I got the same error
Error: {"status":"Unprocessable Entity","message":"Validation error","details":{"errors":[{"name":"in","details":"Value must be one of expected values","path":["fields","richTextBody","en-US","content",5,"content",3],"value":{"data":{},"content":[]},"expected":[{"$ref":"#/definitions/Inline"},{"$ref":"#/definitions/Text"}]},{"name":"in","details":"Value must be one of expected values","path":["fields","richTextBody","en-US","content",20,"content",2],"value":{"data":{},"content":[]},"expected":[{"$ref":"#/definitions/Inline"},{"$ref":"#/definitions/Text"}]}]},

Any idea on how to solve this issue?

For me it was when I had a space (or some other text charcter) in the content without properly being converted into rich text.

The language thing can be ignored, Contentful will always return its error messages referring to en-US irrespective of what you have set in the space.

Thanks.
I figured it out that in my case it was caused by missing nodeType in one of the nodes.