Unknown VS Bad tag quality

I have a project where I communicate with scales via modbus TCP. The scales get powered down when the line is idle.

As you can see I have 2 different tag quality indications. Line 7 is Unknown, and Line 8 is Bad Quality. In both cases, the driver status is the same; toggling from Connecting to Faulted.

So why do I have two different qualities?

My guess is that Line 7 has been offline since the modbus driver started, and Line 8 communicated for a while and then powered down. But the Ignition gateway has been running uninterrupted for a month. And Line 7 has definitely been online more recently than that.

I have not made any changes to tags, which I’m sure would reset statuses. I have made changes to graphics and scripts, and published the project. Would that publish reset the modbus driver, or the tag statuses?

What is the value associated with the ‘Unknown’ quality? Is it 600 or 256?