Hi,
Unspecified values in an evar report is an expected behavior because of its persistence. It depends which metric you are using in an evar report. Below is the document that will explain in detail about unspecified.
None, Unspecified, Unknown, and Other in reporting
If you are using Visits, Unique Visitors et cetera then you would see Unspecified values.
However, if you are trying to check how many times that evar fired. I will suggest you to please use Instances metric. As instances will show you number of times the evar fired and will not show unspecified.
https://docs.adobe.com/content/help/en/analytics/components/metrics/instances.html
Lets take an example here:
Visit 1:
Visitor visits page A(eVar1 was set to "abc") > Page B(no eVar1 was set)
Visit 2:
Directly visits Page B where no eVar1 is set
The reports would be as below:
eVar1 Visits
abc 1
Unspecified 2
Total Visits 2
Let me know if this helps.
