If your using streaming try switching back to polling briefly and see if that clears it
Strange ladder
It was only added in V1.46 so you will of needed to of downloaded a version new than that, even then its turned off by default, but if you look at the bottom right you'll either have the word 'Streaming' or a series of numbers if your using polling
No probs, so it rules that out Streaming as being a possible cause, so I'd just continue to eliminate the other suggestions that have put forward