UParticleSystemComponent plays immediately upon initialization

Development Programming & Scripting
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I am going through the variable, timers, and events tutorial and have one question about deactivating the included P_Explosion asset. I have decided to try to load the asset with c++ instead of using a blueprint as shown in the tutorial.

As of now I have it working by using ParticleSystemComp->Deactivate() and ParticleSystemComp->Activate() in an attempt to hide the explosion until the countdown finishes.

And I am initializing ParticleSystemComp in the ACountdown() constructor at program start.

However, when this gets initialized, the explosion plays, even though I am attempting to call Deactivate() immediately after creating the object. It then plays again at the desired time when calling Activate() in CountdownHasFinished().

After seeing the suggestion in Rider, I looked more into DeactivateImmediate to see if that would hide/prevent the Particle System from showing at program start.

Unfortunately, when I use DeactivateImmediate() in place of Deactivate() I get a runtime error and Unreal crashes/closes:

Countdown.cpp:

#include "Countdown.h"
#include "UnrealExp1.h"
#include "Components/TextRenderComponent.h"
#include "Particles/ParticleSystem.h"
#include "Particles/ParticleSystemComponent.h"


ACountdown::ACountdown()
{
    // Set this actor to call Tick() every frame.
    PrimaryActorTick.bCanEverTick = false;

    CountdownText = CreateDefaultSubobject<UTextRenderComponent>(TEXT("CountdownNumber"));
    CountdownText->SetHorizontalAlignment(EHTA_Center);
    CountdownText->SetWorldSize(150.0f);
    RootComponent = CountdownText;
    CountdownTime = 3;

    const wchar_t* ParticlePath = TEXT("ParticleSystem'/Game/StarterContent/Particles/P_Explosion.P_Explosion'");
    static ConstructorHelpers::FObjectFinder<UParticleSystem> ParticleSystemAsset(ParticlePath);
    ParticleSystemComp = CreateDefaultSubobject<UParticleSystemComponent>(TEXT("Particles"));
    ParticleSystemComp->SetTemplate(ParticleSystemAsset.Object);
    ParticleSystemComp->DeactivateImmediate();
}

// Called when the game starts or when spawned
void ACountdown::BeginPlay()
{
    Super::BeginPlay();

    UpdateTimerDisplay();
    GetWorldTimerManager().SetTimer(CountdownTimerHandle, this, &ACountdown::AdvanceTimer, 1.0f, true);
}

// Called every frame
void ACountdown::Tick( float DeltaTime )
{
    Super::Tick(DeltaTime);
}

void ACountdown::UpdateTimerDisplay() const
{
    const int MaxTime = FMath::Max(CountdownTime, 0);
    CountdownText->SetText(FText::AsNumber(MaxTime));
}

void ACountdown::CountdownHasFinished() const
{
    ParticleSystemComp->Activate();
    CountdownText->SetText(FText::FromString("BLAM!"));
}

void ACountdown::AdvanceTimer()
{
    --CountdownTime;
    UE_LOG(LogTemp, Warning, TEXT("CountdownTime: %d"), CountdownTime);
    UpdateTimerDisplay();
    if (CountdownTime < 1)
    {
        GetWorldTimerManager().ClearTimer(CountdownTimerHandle);
        CountdownHasFinished();
    }
}

I also tried to declare the FObjectFinder in the header and make it into a class field/member so that I could just call it when needed, but that also did not work.

How can I get the particle system to play just once in CoundownHasFinished() and prevent it from playing in when the program starts?

Any suggestions are greatly appreciated… thanks!