QTextCursor movePosition() sometimes won't reach the end of text

I'm writing an app which uses a QTextEdit to contain text. It also uses hunspell to check spelling, and for that, I use QTextCursor::movePosition() to move from word to word. The code looks like this:

// code placeholder
do { 
   while (cursor.movePosition(QTextCursor::EndOfWord, QTextCursor::KeepAnchor)) {
       textEdit->setTextCursor(cursor); QString word = cursor.selectedText();
 // etc
// Move to the next word
>if (! cursor.movePosition(QTextCursor::NextWord, QTextCursor::MoveAnchor))
 break;
 } 
}
 while (cursor.movePosition(QTextCursor::NextBlock, QTextCursor::MoveAnchor)); 

I've found that, if the text contains something like

word word word1

<blank line>

<space: one or more> word2 word2 word2

then movePosition(QTextCursor::NextWord, QTextCursor::MoveAnchor) won't move past word1: it returns false, and we break out of the loop.

Also, if there's another line below it that doesn't have leading spaces, as

<space: one or more> word2 word2 word2

<blank line

word3 word4 word5

then it'll proceed to word5.

Yes, I know it's confusing, which is probably why it's not been reported before (as far as I can tell). Sorry if I've messed up the code view: this is my first bug report for you.