Stop rejected - invalid price

Just when I thought I had bracket orders working through the API this popped up this morning. Below is a sample order I’m sending through but I keep getting an error on the STOP bracket. The trade submits but the STOP order is rejected with a message of ‘Invalid price’

{
“accountSpec”: “XXX”,
“accountId”: XXX,
“action”: “Buy”,
“symbol”: “MESM5”,
“orderQty”: 1,
“orderType”: “Limit”,
“timeInForce”: “GTC”,
“price”: 6097.75,
“bracket1”: {
“action”: “Sell”,
“orderType”: “Limit”,
“price”: 6112.75
},
“bracket2”: {
“action”: “Sell”,
“orderType”: “Stop”,
“stopPrice”: 6087.75
},
“isAutomated”: true
}

This seemed to work fine last week so I’m not sure if something has changed.

invalid price usually occurs when the current price is below the stop price(in case of a sell stop)