Regarding the above question, I have temporarily resolved it myself.
I’m not sure if the correction method I used is the correct one, but the issue has been improved for now.
If there is a proper correction method, I would appreciate it if you could let me know.
Location of the code:
Engine\Plugins\Online\OnlineSubsystemEOS\Source\OnlineSubsystemEOS\Private\OnlineSessionEOS.cpp
Code after modification:
void FOnlineSessionEOS::OnLobbyUpdateReceived(const EOS_LobbyId& LobbyId)
{
const FUniqueNetIdEOSLobbyRef LobbyNetId = FUniqueNetIdEOSLobby::Create(UTF8_TO_TCHAR(LobbyId));
const int32 index = GetDefaultLocalUserForLobby(*LobbyNetId);
const EOS_ProductUserId LocalUserId = EOSSubsystem->UserManager->GetLocalProductUserId(0 <= index ? index : 0);
Code before modification:
void FOnlineSessionEOS::OnLobbyUpdateReceived(const EOS_LobbyId& LobbyId)
{
const FUniqueNetIdEOSLobbyRef LobbyNetId = FUniqueNetIdEOSLobby::Create(UTF8_TO_TCHAR(LobbyId));
const EOS_ProductUserId LocalUserId = EOSSubsystem->UserManager->GetLocalProductUserId(GetDefaultLocalUserForLobby(*LobbyNetId));