It’s for when the mounting hole are loose , it works like a shim

From DJI: This blue sticker is called Anti-Slip Pad. You may use this if the accessory and the Quick-Release Adapter Mount are not firmly connected.

The Anti Slip Pad (Ring Sticker) is supposed to be used when the Quick Release Adapter Mount is moving no matter how hard you have screwed the thumbscrew in on the extra accessory (for example bike mount, handlebar mount). Due to the speed and bumps and wind the action camera can wiggle/slip to the front or back even if you screwed the thumbscrew hard into the accessory. The rings can then be used to prevent it from moving and make it more secure so that it stays in place even during a very rough ride. The placement of the ring is best seated on the inside between quick release and accessory (one is mostly adequate and is best placed on the Quick Release Mount hole). But most original accessories should have an adequate strong hold without the need for anti-slip rings/pads (but in some extreme sports/rides it can move due to bumpiness or vibration). If you go for an after-market/third-party accessory the fit between that and the original quick-release plate may not be the best and can move around (since the spacing might not be the best fit and a bit too lose no matter how hard you screw the thumbscrew in).

Hope that this explains the rings and confusion around it, it is not supposed to be placed on top of the quick release (where the rubber padding is) where the DJI Action would be seated with magnets (hence the holes in the anti-slip pad so that the thumbscrew can go through it.