Stately: java.util.ConcurrentModificationException:, even when using stately's concurrent classes 👀

Exception java.util.ConcurrentModificationException:
  at java.util.ArrayList$Itr.next (ArrayList.java:860)
  at co.touchlab.stately.collections.ConcurrentMutableIterator$next$1.invoke (ConcurrentMutableIterator.java:11)
  at co.touchlab.stately.collections.ConcurrentMutableIterator.next (ConcurrentMutableIterator.java:16)
  at arrow.core.IterableKt.flatten (Iterable.kt)
  at in.shabinder.shared.provider.query.DefaultQueryResolver$getRelatedSongs$2$invokeSuspend$$inlined$buildParMergedIorNelSafely$1$1.invokeSuspend (DefaultQueryResolver.java:165)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (BaseContinuationImpl.java:12)
  at kotlinx.coroutines.DispatchedTask.run
  at kotlinx.coroutines.internal.LimitedDispatcher$Worker.run (LimitedDispatcher.java:4)
  at kotlinx.coroutines.scheduling.TaskImpl.run
  at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely (CoroutineScheduler.java:1)
  at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask (CoroutineScheduler.java:63)
  at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker (CoroutineScheduler.java:63)
  at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run (CoroutineScheduler.java:63)