Greetings,
There are a couple reasons that I know of that could cause the "Value Bad" status for a tag. The most prevalent is that the channel is not configured correctly in Measurement & Automation Explorer (MAX). Are you able to test all the channels in MAX while you are getting the "Value Bad" status?
Additionally, you will get this error if you are looking at the same analog input or digital line with the same tag.
Is the problem permanently solved when you switch to Device instead of Cache?
To troubleshoot, I would simplify everything and just try to measure a very small number of tags and see if you get the same error.
