TextArea.selectionEnd sometimes returns an incorrect value

Steps to reproduce:
1. Run qtquickcontrols/examples/quick/controls/text (one of your examples);
2. Click a word in the paragraph starting with "If you are viewing this document" three times to select the whole paragraph.

Expected results:
Nothing happens.

Actual results:
The font of the selected paragraph becomes as large (16) as the font of the following heading of "Font and Paragraph Styles".

Note:
If the binding at the bottom of main.qml:

selectionEnd: textArea.selectionEnd

is changed to:

selectionEnd: textArea.selectionEnd > 0 ? textArea.selectionEnd – 1 : 0

the issue seems to be fixed, that is, it cannot be reproduced any more but it's not clear if this workaround would not cause other problems.