Puq Press 15g issue

We use 15g VST baskets at our cafe and we have a Puq press.

I seem to keep having an issue with a lack of compression on the coffee puck. I have the Puq press set to 30kg of pressure and even with adjusting the clamp to the tightest it can go for the portafilter the coffee puck will still sometimes be able to fall straight out of the basket if held upside down.

If anyone has any suggestions on how to combat this I’d appreciate it very much.