This does not affect the host. Players connected over LAN are taking brief suffocation damage (we know the type because it has been fatal, showing a message of how the player died) when they are not suffocating. It happens in areas where no blocks are moving or being broken or placed. There is no noticeable lag at the time. It is not hunger or enemy damage.

Unfortunately we have found no steps to reproduce the problem reliably. Perhaps a confined area such as a cave, so there are more blocks nearby to suffocate in?

Host device is an iPhone 6S, but that is not an option in the menu. Connected devices are another iPhone 6S, an iPad 1, an iPad 2 and an Amazon Kindle, and the problem appears on all of them.