Simon,
I agree with Ian, most likely a different setting in SkyDemon/Settings/Navigation Options, - e.g. Show within Vertically +/-
Also possible if it was a 'Bearingless' Mode C/S target (which shows as a coloured ring), that you don't have 'Show Bearingless Targets' selected on one of your devices (in the same Dropdown as above)
Regards
Peter