Message Attributes empty

[jameswilsterman]

The "messageAttributes" object is empty on incoming events even though my messages all should contain one attribute.

"messages": [
{
"messageId": "a5df8a12-ae1d-4a1d-b352-c8aafbe4dc4b",
"receiptHandle": "AQEBtYpGgK/MU2rTPCMsV8f+glYkIZ+Jbsptce9qPk4+00y9cOwsP33I9zj8+U0OA0jt4UTkhf/4igPE/mOhz37TFCOEGtkEB12sRNgN+bufASfwFGIUQ5tSYJIZ9QduULuO15IDFH0JAVrOIdq8ZSM3BLcV3EiD7VXha2CIg2mXmqkpcJyfcVl6kVN9WjYCWLBto6RGorejeJ9dAsn7AJcYr546oXk4z5z0q79NRq59F4Q3DESsmNYvGqjOOHOs8aJ5OXzKM4EaH7ZZwhsU+lDocNMqMLOPRPY3J34sbK4A4Te1lsOSkGE9T1CnijwZBnO00mUB/7vpvfPrXs+j/2riz7pqf8mT8Ygwblry+KKz7wTUbLt5fFpgAJqm2QUSvIdu2DI+I4b+4b3ro6OMa/G3Nw==",
"mD5OfBody": "2301f613c4160a6cf522a340da376150",
"body": "{<EXAMPLE_BODY>}",
"messageAttributes": {}
},
{
"messageId": "7c5200d2-22be-4d62-a7b1-9ac6aac2218c",
"receiptHandle": "AQEBo1djdqdLSi5Hwzy8lxcYW9C9H/kxc5pfbbLDaQhOPUFARuOlRMaahEqGU6+GrCUYnzO2CEnoIiBm6DHK3LMN7HO2RfRC/iMLjmkFbLLkWKwL2R9IsH3r6t7kiuYWfbYD0fCh0a/Cl/xkwBrE+WCfJCX3Flkl1zR5zZD/EBmnkx20PKu5u6fEGofJNKm17SAqr8IVh6eDyBb9zHig5sUvCWDrByH9jpW3gaxSKLAHJHAEIj1uyHhxGS39SaqJA6LydxsA+xwZwOjX4PYxuMT7yXgmrVm/vWQ//uL7vy1dX/BydNdSqt+4ZKJ71/phHx5TmrKS1RDDJc/enrKOw6EJTcT9ECtDg2DPjEJyspTp2n2UMTvzLbSf4kysxg1znFffnr2OOpqIRpCglE45cixi2Q==",
"mD5OfBody": "7295178dfd60ce94607294d7460fd4b7",
"body": "{<EXAMPLE_BODY>}",
"messageAttributes": {}
}
]