The `matrix_need_update` variable needs to be reset to `false` in `transfer_matrix_values()`, otherwise that function continues to be invoked for every scanning loop (forever with `sym_eager_pk` and `sym_eager_pk`, or until some key gets released with `asym_eager_defer_pk`), and the scanning rate gets much lower because of all that useless work. Co-authored-by: Sergey Vlasov <sigprof@gmail.com>