QTextEdit signal textChanged() is emitted even if the editor contents was not changed

The signal textChanged() in QTextEdit is emitted when first the editor is focused and then one clicks outside the editor and then back in. The signal is emitted even if the editor was not changed.
This bug does not appear in qt 4.8.4.

Attached an example to test this.

This also happens with the contentsChanged signal os the QTextDocument associated with the QTextEdit in question.