Intermittent Rocky Context Error

I’m getting an error intermittently from my Rocky app. I’m using long polling to register events from my device to a mobile app. The app reaches out the the agent, the agent to the device. When the device registers an event, it responds to the agent, and then to the app. If the request times out by the Rocky timeout setting, it alerts the app, and the app sends a new long polling request. This all works properly most of the time. I am passing the context.id to the device and back again to keep track of requests and contexts properly. However, every now and then, when the device gets an event it sends to the agent, and when the agent checks if the context is complete or not, I get this:

[Agent] ERROR: the index ‘isComplete’ does not exist

I started logging the context ID to make sure I actually have a context before I check if it is complete, and I always do, so why would the “isComplete” index not exist?