Inserting a new line (not new paragraph) in a QTextEdit causes the caret to draw incorrectly until the next character is inserted

STEPS TO REPRODUCE
1. Build and run the attached test app.
2. Type 'TEST' into the text edit.
3. Press Shift+Enter to insert a new line.

EXPECTED: The caret moves to the start of the new line, with the correct size.
ACTUAL: A correctly-sized caret draws too high on the new line, and an incorrectly-sized caret blinks at the start of the line.

4. Now type another letter T. Observe that the caret corrects itself.

I've attached screenshots demonstrating the problem.