CROSSED DOMAINS? Google mistakingly associating MSM content from one domain with another

We have used EE and the MSM for 7+ years now and upgraded from version 1 to 2 years ago. No real issues. We run our main site which I will call domian1 and a secondary site called domain2 both from Multisite manager. Each has somewhat similar topics but very unique content.

Recently I did a “site: domain1” search on google and was surprised to see pages from domain2 being indexed but listed with Domain1 URL.

Google Search Result Example for Domain 1:

Domain 2 Title Page Domain 2 page description www.domain1.com/domain2pages/etc

If you click on this, it takes a long time but it renders a page that looks like Domain2 but has still has www.domain1.com in the url.

Google indexes Domain 2 correctly on other searches and I would haven’t had found this if I wasn’t looking at how google indexes Domain1.

I’m worried that google will penalize us (or is already has) for duplicate content. I’m guessing this has something to do with the Multisite manager but don’t know where to begin. Has anyone come across this before? Any thoughts??? Thanks