Error on rapid board after adding issues into the sprint

Symptoms

The below exception is thrown when trying to drag and drop cards:

Exception: Uncaught TypeError: Cannot call method 'done' of undefined
Resource: http://jdog.atlassian.net/s/en_US-pdht6n-418945332/813/47/f642fc5b3eb59a1ea7d18c77bc8eb1bf/_/download/contextbatch/js/gh-rapid/batch.js
Line: 2914

Notes

his has happened a couple of times now. I dragged some issues into my active sprint then clicked 'work'

I get this error but the page still loads properly and the error goes away when i refresh