Below is a quote I left on the " Homekit bridge to OH3 lost" Topic. It could explain what is happening. I don’t think a fix has been pushed out yet so I believe this issue is still active.
I have avoided editing the configure file and saving it via OpenHab3 UI for nearly 30 days now and I have not lost my Hub or seen unresponsive items in Home App due to the lost Hub.
Just as a note, I have not made any changes to the private wifi address setting. my iPhone is currently running the latest iOS 14.6.