It seems I've got what do you mean — after clicking on «Quote», the quotation marker is not reset and still kept in memory. So, the next time you click on «Quote», the script supposes if there's something in memory then it's selected.
But it lasts only until the cursor is appearing/blinking in the post form. As soon as you click anywhere on the page and the cursor disappears, the marker is reset. At least this is how it works in desktop browsers — on mobile devices, this status seems to be reset immediately.
Anyway, here would be a simple solution (I'll apply it for the next official release, but it should work right now on these forums already):
— open
form.js for editing
— locate the code string ending with:
bbCode2='[/quote]'; endOfLine='\n';
— after this, enter/paste:
selektionEvent='';
Let me know if it worked for you.