I believe the issue was that EsriMap is performing a react.Clone of its children, but a null object was being passed as a child if path.length was zero, which caused a problem. Currently fixed by passing an empty fragment if path.length is zero. It may be cleaner to always render the path component and handle the empty coordinates array in there, but I'll leave that you @mbwatson if you want to investigate that.
I believe the issue was that EsriMap is performing a react.Clone of its children, but a null object was being passed as a child if path.length was zero, which caused a problem. Currently fixed by passing an empty fragment if path.length is zero. It may be cleaner to always render the path component and handle the empty coordinates array in there, but I'll leave that you @mbwatson if you want to investigate that.