Pen Tool Creates Empty Shape Layers with No Stroke

When I use the pen tool to create a stroke, every time I click it creates a new empty shape layer, instead of a stroke and a path. 

It works in other comps within the same project, and even worked in the exact same comp minutes before but then started doing this. 

Have I disabled something? I've checked all settings and they seem fine. 

I've cleared cache, re-started AE, rebooted my machine. I have a feeling it's a setting and I'm being an idiot. Please can someone assist?



After Effects 2020
17.1.2

iMac Pro 2017

Catalina 10.15.7
3.2GHZ 8 Core

32GB Ram

Radeon Pro Vega 56 8GB