Powershell concurrency with Start-ThreadJob and ForEach-Object -Parallel

Question

I've been trying to implement a producer-consumer pattern with multiple producers using BlockingCollection<>, Start-ThreadJob and ForEach-Object -Parallel. The results were mixed. Some code runs, some freezes and some just crashes powershell. So I'm thinking, I must be doing something fundamentally wrong:

using namespace System.Collections.Concurrent

class TestProducerConsumer
{
    [int] $result = 0

    [BlockingCollection[int]] $queue = 
        [BlockingCollection[int]]::new()

    [void] producer([int]$i) { $this.queue.Add($i) }

    [void] consumer() {
        $sum = 0
        $it = $this.queue.GetConsumingEnumerable()
        foreach( $i in $it ) { $sum += $i }
        $this.result = $sum
    }
    
    [void] Run() {
        $job = Start-ThreadJob { ($using:this).consumer() }
        1..10 | ForEach-Object -Parallel { 
            #($using:this).producer($_)     # freezing
            ($using:this).queue.Add($_)    # working
        }
        #Start-Sleep -Seconds 1             # freezing
        $this.queue.CompleteAdding()
        $job | Receive-Job -Wait
    }
}

$t = [TestProducerConsumer]::new(); $t.Run(); $t

In the simplified test case above, there are two lines doing the same thing: One is getting the queue member from the instance and adding the value directly; the other is calling a method on the instance to add the value to the queue. The former works, the latter freezes!?

Also, adding back in the line with Start-Sleep freezes the process.

Tested on Windows 10 with various PowerShell 7.* versions.

EDIT: Probably related to ForEach-Object -Parallel situationally drops pipeline input and similar issues