Uninitialized scalar field

The field will contain an arbitrary value left over from earlier computations. A scalar field is not initialized by the constructor
/src/mongo/db/pipeline/document_source_group.h:298: UNINIT_CTOR 120718 Class member declaration for "_sbeCompatible".
/src/mongo/db/pipeline/document_source_group.cpp:409: UNINIT_CTOR 120718 Non-static class member "_sbeCompatible" is not initialized in this constructor nor in any functions that it calls.