Upload restarts automatically after interrupt

We are using a progress dialog with a Cancel button within an Upload component. But when user press Cancel button (interruptUpload method call) Upload starts uploading again (calls two methods com.vaadin.ui.Upload.StartedListener#uploadStarted and then com.vaadin.ui.Upload.Receiver#receiveUpload). Sometimes it stops uploading in 1 second after restart, but sometimes fiinsh the uploading successfully. If user press Cancel again, Upload may start uploading one more time - repeat up to 3-5 times. How to avoid this behaviour?
Also a have noticed, that the Upload#interrupted flag is not declared volatile nor protected by synchronized section. But as i can see it may be accessed by several parallel threads. Isn’t this a problem?

The same problem in MultiFileUpload addon (tested in debug mode).
Especially when UploadStateWindow used in modal mode.

Did you guys file a bug for this? I am having the same issue.

No, we did not.
The issue is present in all latest versions of Vaadin 7 and were not fixed.