Can someone please explain to me why the XCSOAR for android program always uses the serial id of "AAA" in the filenames for the .igc file it creates?

From page 18 of the 31 May 2019 IGC GNSS FR Technical Specification:

Long file name: 2015-06-17-MMM-XXX-02.IGC
MMM = manufacturer's three-letter IGC identifier (see table on next page)
XXX = unique FR Serial ID (S/ID); 3 alphanumeric characters
02 = second flight of the day

So according to the IGC specification, the Manufacturer's 3 letter IGC identifier and the unique FR serial ID should produce a unique file name. However, XCSOAR does not output a unique Serial ID, it always outputs "AAA". For example:

2019-06-07-XCS-AAA-01.igc

The problem arises if more than one pilot at a contest is using XCSOAR, then the scorer will receive .igc files from different pilots with identical filenames.

Is there anyway for the pilot to configure XCSOAR to output a serial ID other than "AAA"?