Why do spawned actors overlap blockingVolumes?

I am having trouble keeping spawned actors on the right side of a blocking volume. The AActor is a Cell and the cell periodically divides to give rise to a daughter cell, which is a highly related copy of the parent. The cells are supposed to fill up an empty compartment and then stop dividing. However cells near a blocking volume give rise to children on the other side of the volume and they continue to divide on the wrong side of the wall. Can someone help me figure out why this is happening and how to avoid it.

I’ve included what I think are relevant portions of the constructor and the spawn event below:

// ... In the constructor I make a USphereComponent for the collisions
iCellComponent = CreateDefaultSubobject<USphereComponent>TEXT("CellComponent"));
	iCellComponent->bGenerateOverlapEvents = true;
	((USphereComponent *)iCellComponent)->InitSphereRadius(40.0f);
RootComponent = iCellComponent;
// ...

// Later the cell divides and spawns a new cell at a nearby location

		// and a random vector a short distance away 
		lLocation += GetActorScale3D()*100.0*rand.VRand();
		lLocation.Z = std::max(1.0f, lLocation.Z);   // an attempt to avoid overlap with blocking volume at Z=0
		FRotator lRotation = GetActorRotation();
		FActorSpawnParameters   lSpawnInfo;
		lSpawnInfo.SpawnCollisionHandlingOverride = ESpawnActorCollisionHandlingMethod::AdjustIfPossibleButDontSpawnIfColliding;
		ACell *lChild = GetWorld()->SpawnActor<ACell>(lLocation, lRotation, lSpawnInfo);

The child cell still spawns overlapping or on the other side of blocking volumes. How can I prevent this?