A few things here...
First, when did you implement the plugin? If it was sometime this month, then those unspecifieds are just the traffic from before you set this up... if it was longer ago, then those unspecifieds are probably just users who aren't getting the cookie.
To be honest, I dropped that plugin ages ago, it's not terribly reliable now.... Basically, all it does it drop a cookie on the user's device and sets the expiry to 30 days (or maybe another specified length of time as per your implementation). Initially the value is "new", and when users come back within that period, the cookie is updated to "repeat"... the problem is that so many browsers are deleting cookies after 7 days, or sometimes less (particularly if these aren't first or secure cookies)... Cookies set by JS (like these) are more susceptible to deletion over server set cookies, and some browsers may be actively blocking JS cookies....
You might want to check out my RockStar tips from 2023 on how to create New/Repeat visitors for a specific period, this relies only on Adobe's ability to stitch / re-identify the same user... which if Adobe treats a user as new, your JS set cookies aren't going be any better.
https://experienceleague.adobe.com/en/docs/events/the-skill-exchange-recordings/analytics/may2023/ro...
