RabbitMQ API returning incorrect queue statistics

Question

I'm working with RabbitMQ instances hosted at CloudAMQP. I'm calling the management API to get detailed queue statistics. About 1 in 10 calls to the API return invalid numbers.

The endpoint is /api/queues/[vhost]/[queue]?msg_rates_age=600&msg_rates_incr=30. I'm looking for average message rates at 30 second increments over a 10 minute span of time. Usually that returns valid data for the stats I'm interested in, e.g.

{
    "messages": 16,
    "consumers": 30,
    "message_stats": {
        "ack_details": {
            "avg_rate": 441
        },
        "publish_details": {
            "avg_rate": 441
        }
    }
}

But sometimes I get incorrect results for one or both "avg_rate" values, often 714676 or higher. If I then wait 15 seconds and call the same API again the numbers go back down to normal. There's no way the average over 10 minutes jumps by a multiple of 200 and then comes back down seconds later.

I haven't been able to reproduce the issue with a local install, only in production where the queue is always very busy. The data displayed on the admin web page always looks correct. Is there some other way to get the same stats accurately like the UI?