I have seen this happen for quite some time. In order to avoid calls disturbing sleep at night I have tried scheduling call forward or do not disturb options with time period of 8pm to 11:45pm. But instead of line coming back to normal status outside this time window, my phone seems to keep honoring the DND or forward as setup for night time. Many callers have complained about not being able to get through or being surprised to see the forwarded number answering the call instead of the home line. The only working solution seems to be is to disable time based schedules and just use call block with specific spam numbers in it preloaded. That works 24x7. I am unable to block landline from ringing at night selectively or otherwise based on time window.
Is this a bug or a known issue ? I tried setting up via different browsers IE Firefox etc and the result is the same.