discard=true does not work

[gahtan-syarif]

C:\Users\Gahtan Syarif Nahdi\Downloads\fast-chess-exceptionhandling\fast-chess-exceptionhandling>fast-chess.exe -config file=config.json outname=something2.json discard=true
Loading config file:  config.json
Discarding config file
libc++abi: terminating due to uncaught exception of type std::runtime_error: Error: Need at least two engines to start

seems it discards the config file at the start of the tournament instead of at the end