Clarification on _id/visitorid cookie storage and unique visitor reconciliation (no replies)

Thanks to everyone in advance!

I have dug into these links and various others already just as an FYI
[piwik.org]
[forum.piwik.org]

We are using the JS tracker and are noticing a massive amount of new visitor ids with the same ip address - which implies that the visitor id cookie is getting reset way before the expiration date (2 years). That said, I have a few questions:

I am trying to understand if this is a standard issue where browsers are deleting tracking cookies or this is a bug?

Should the expectation be that visitor id is fairly ephemeral and you need to rely on additional fingerprinting in order to draw out unique visitors?

In regards to reconciling visitor ids under as a unique visitor, we are looking at ip address+user agent+browser features as a finger print, this seems like the most reasonable way per my results found in this forum?


Thanks again!

Sam