My Philips Avent Grow nipple collapses

If the Grow nipple collapses and is drawn into the bottle, this could be because the anti-colic feature is closed off. Nipple collapse appears when the vacuum inside the bottle is too high. This is most likely caused by assembling the screw ring onto the bottle container too tightly. If this happens, air cannot get into the bottle. Unscrew the ring slightly to allow air to come into the bottle again.