The track feature has nothing to do with the map card ... The track can be created and/or saved whether there is a map card in the unit or not ...
Assuming you did indeed use the "Save Track" command to save the current track ...and that track was indeed saved to the
internal memory of the unit ...
We have seen instances in the past where a full trackpoint cache causes weird anomolies in Chart function ...
The trackpoint cache can hold 20,000 trackpoints (depth and position data) until the cache is full and starts overwriting the first trackpoints created and stored in the trackpoint cache (in the background - you can't see the cache data - you only see the track on the Chart behind your boat icon created from those trackpoints created in the cache) ...
It has been advised that clearing the trackpoint cache occasionally (Clear Track command) can sometimes help eliminate these weird Chart anomolies that no one has a difinitive explaination for ...(this is why the "Clear Track" command has been added to the Chart view Xpress "Menu" where it's easier to get to) ...
I always advise to clear the current track at least once a day ... To possibly ward off these anomolies caused possibly by a full trackpoint cache ...
I do not know for sure this is your issue ... But it is a possibility ...
Rickie