I suspect that is the case, as otherwise, the centreline for a the closest runway would permanently be being displayed, which probably isn't what you want when you're still outbound or exploring.

Maybe the centreline display for the "fly-near" airfield could be an option, as one could alter (reduce to a suitable number) the distance at which the approach data appears.  This would be useful for local circuits.

A slightly clunky workaround is to touch the airfield icon to popup the 'What's Here' panel, then select 'Routing' and 'Route direct'. This will replace your magenta circle with a DCT line, but will display the centreline fleche if you have approach tools enabled and are within your specified radius.

Thanks I will try that and see whether it works ......