To reproduce, run the example and guess some letters. When you select some correct letters, they will appear on top of each other.

Tested on a Pixel C.

From the Word.qml:

            Letter {
                id: letter
                text: word.text.charAt(index)
                width: (word.width / word.text.length) - row.spacing
                height: word.height
            }

If I replace the width with

                width: (word.width / word.text.length) - 18

Then it works correctly (18 is the last value of row.spacing based on output from a onSpacingChanged handler). This is why I set the component to the QML engine, since everything else seems to work correctly.