blinkCursor does not turn off

[griffj]

The blinkCursor function does not seem to work correctly. I can start the cursor blinking with:
lcd.blinkCursor({
blockIndex: 10,
stop: false
});

Which works fine, but if i try to turn the blink off with:
lcd.blinkCursor({
blockIndex: 10,
stop: true
});

it continues to blink