How to debug: Uncaught TypeError: dmxRouting.js:7 Cannot read property '0' of null

Hi all,

Getting this error:

Uncaught TypeError: dmxRouting.js:7
Cannot read property '0' of null
    at n.update (dmxRouting.js:7)
    at n.$update (dmxAppConnect.js:7)
    at dmxAppConnect.js:7
    at Array.forEach (<anonymous>)
    at n.$update (dmxAppConnect.js:7)
    at dmxAppConnect.js:7
    at Array.forEach (<anonymous>)
    at n.$update (dmxAppConnect.js:7)
    at dmxAppConnect.js:7
    at dmxAppConnect.js:7

This is happening in a few pages - and I believe is the root cause of some data not displaying unless I scroll - then it renders.

Can anyone point me towards how I would debug something like this, so I can find and fix the issue?