Apart from reading the ColorMFA user manual from their Wiki
, you’ll also need to adjust the setup of your RNS-E Sir.
It looks to me that the compass option is ticked which pushes navigation information to the instrument cluster at all times regardless of you not selecting a destination. The compass can be useful in certain circumstances but can be easily turned off in seconds. This will save you having to change the user defined setting on ColorMFA or swapping the display via the DIS stalk every time you switch the ignition on.
First up navigate to the RNS-E Nav page then select Setup:
View attachment 107940
Which will take you to this page, scroll down to the second page by rotating the large dial/know inside the quadrant buttons:
View attachment 107941
You’ll end up on what’s displayed below. simply continuing to scroll down with the same dial to Compass. I’m guessing yours looks like this:
View attachment 107942
By pushing the large dial/knob it will untick the Compass selection:
View attachment 107943
This will stop navigation information being sent to the instrument cluster when no destination is selected. It will of course send the necessary navigation information to be displayed on the instrument cluster when an actual destination has been set.
Hope this helps and have a read of that Wiki.