Based on what you've described, at this stage, I don't expect it is a bug in the platform. If the PC was off and the driver tried to connect using the websocket interface, it makes perfect sense for it to report a warning that the host was unreachable. The question is more why the behaviour changed. It could be as simple as they added in a warning entry that would automatically get logged against the device.
Yeah, I raised this a few years ago further up in this thread and I think changing the value to something larger should be fine. But like you say, it only spaces them out. I expect what you will likely want to do is find a way to determine when the PC is off and somehow tell the PC controller device to stop trying to connect (not sure how exactly). You could try using an energy monitoring plug if you have one handy, to tell when the PC is on/off. What you could do with the PC Controller device, not sure..
