By default a visit is over after 30 minutes of inactivity or at Midnight (when a new day starts). The hits limit may be BOT related. 2,500 is a lot of hits if a human is initiating them. 

There's plenty of thunder to go around 

Assuming that variables are enabled, this is probably an issue with the setup in the Product Profile within the Admin. Go into the admin under the Analytics Product Profile and go to Permissions. Ensure that all the reports you want to use are enabled under Dimensions and Metrics. 

The campaign report will contain the value passed into s.campaign. If that has data and your classifications do not, the classification rules are the issue.

Any traffic that does not contain a tracking code will show up as "unspecified" if you are using metrics like visits. If all your traffic is "unspecified" and you know some contained tracking codes, check to see if there is a redirect occurring. The redirect will not forward the campaign information...

If you are using a cookie preference tool like OneTrust, it is likely that the page is reloading before the server call fires. If that's true, the referring domain in the users browser would be your sites and would be treated as none or a session refresh depending on your campaign processing rules.

I use 3 event variables. One for 25%, 50%, and 75% scroll. I only fire the additional scroll calls on templates where the scroll really matters. As Jen mentioned, you will increase your server call volume.   I then created calculated metrics for scroll rates and use 50% scroll rate as a content KPI ...

(Saint) Classifications are used to apply metadata to values within a report. Campaign tracking codes (passed into the s.campaign variable) are similar to UTM codes with the exception that in Adobe Analytics you use a single code rather than multiple codes. You can set up your own format for the cam...

If the tag is firing immediately when the page first loads, time metrics shouldn't be affected. As @FrederikWerner stated, time is the difference between two time stamps.  If the tag is being delayed when the page loads, users may be clicking off the page before the original page tag fires causing s...