First off, the connection to the crankarm (hidden one)

Now, all the other connection points on the SRAM one are different to the crankarm one, as seen here

Here is the profile of the cutout on the crankarm (BB30 compact). You can see why the cahinring has some different machining.

All makes sense now. For BB30 Compacts, the Praxis rings need to be filed slightly to match the profile as per the SRAM 50T chainring

Problem solved.
