There should be some read checks to see if video is ready or not. These types of requests would happen as your video is being uploaded, verified and processed and is corresponding with the events that would need these details.
The last one that would fire, and which could cause more video request pooling would be the ready_to_play.
Having that said of course, the same is not available in r27. My suggestion would be to make a quick check on some local page by setting it up with a test against our current stable (r30) or latest (r32).
This would tell you if the same exists in a later revision.
* We have made many changes since r27 to r32 and have some in motion for r33 so each revision brings few improvements and sometimes new available events.
If the same continues, it might be better to create a ticket instead so that you can share a link with us privately allowing us to inspect the specific case and see what might be happening.
PS: You can just add them as link references, no need to compile it all for a quick test.
Copy paste it and you are ready to go. Of course please do let us know how it goes.