What are you trying to say? %value% will be the trigger value for the trigger event. So, in this case "good" would the %value%. The only way you can have an event with no value is if the driver creates an event with no value which is really not something that a driver should be doing. It's part of the whole event system that every event have, at minimum, a name and a value. What driver are you using to generate the data? It seems to not be following any of the Hubitat standard capabilities. Do you have the capabilities reference for you use when writing a driver?
The driver doesn't sync with Rule Machine. Rule Machine queries for the necessary device attributes when the rule is triggered. And the variable %value% is definitely set to the trigger value of the event.
If you modify attributes on a device within a rule, RM won't know about those changes since they are loaded when the rule fires. So, at the beginning of rule execution. It assumes that since you are setting the attribute within the rule, you would have no need to query it's value, since you just set it. I don't understand why you need to set the attribute to anything. Why no use a local or global variable instead of a device attribute?