ERA : Symbol not found, but how exactly?

Hi,

Error Name: Symbol Not Found Error
Occurrences: 1
First Occurrence: 2020-04-30
Last Occurrence: 2020-04-30
Devices:
    Forerunner® 245 Music: 3.00
App Versions: 1.0.6
Languages: deu
Backtrace:
    Tracker.doTrack:85

For reference, line 85 of Tracker.mc is:

lapCountIn++;

Obviously, that would make sense if I had not initialised the lapCountIn value, but it is initialised during Tracker.initialize() on line 30:

lapCountIn = 0;

And I have searched the entire code base for anywhere it is set - there is only one other place in the code where it is reset:

var i = tracks.size();
do {
	i--;
	tracks[i].lapCountIn = 0; // Setting individuall properties appears more efficient than having a class method, in this instance
	tracks[i].lapCountOver = 0;
} while(i > 0);
 

For memory, I checked running on that device and I had 26.5KB / 60.0KB while running with a peak of 29.5KB so it looks like there was plenty of memory to spare, too. So, pretty sure my code is in the clear for this one. Is there something else that could have happened?

Cheers,