Annotations not saving due to invisible values

Bug Reports
1

Platform: Website

Browser, if a website issue: Chrome

URLs (aka web addresses) of any relevant observations or pages: https://www.inaturalist.org/observations/53461553, https://www.inaturalist.org/observations/59589078

Screenshots of what you are seeing:

Screenshot_20250905_105728
Screenshot_20250905_105728763×551 31.8 KB

Description of problem:

Step 1: Try to add life stage annotation

Step 2: Get error dialog “Failed to save record. Please try again later.”

The devtools show the following HTTP response:

{
    "status": "422",
    "errors": [
        {
            "errorCode": "422",
            "message": "{\"error\":[\"Controlled attribute cannot have multiple values\",\"Controlled value has already been taken\"]}",
            "from": "externalAPI"
        }
    ]
}

I seem to remember a previous issue with such errors, but I cannot find the forum topic. Possibly the cause was an out-of-date index somewhere?