Hi @dry-elephant-14928, thanks for taking the time. In the meantime I switched to a custom UI not using the UICollectionView but a bunch of UISwitches - as in our usecase we know how many and which remote participants can be expected.
Nevertheless, I'll explain the issue a bit more:
I started with the uikit-minimal example which is using a UICollectionView to display all participants in a call. I do further filter the remote participants though because in our case not all of them should be shown to the user. The ones that are shown can be muted/ unmuted (or in LiveKit terms subscribed/ unsubscribed) by tapping on them. This is where I'm having issues. The 'didUnsubscribe' delegate function does not fire for one (in my case the last one) of the remote participants.