UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.102 Safari/537.36

Steps to reproduce the problem:
1. Go to Google analytics console and see a drop in customer traffic.
2. Go to an internal system and notice there was no actual traffic drop. 
3. The problem seems to be with Google Analytics not tracking customers on this new browser?

What is the expected behavior?
Google analytics should not show a drop in customer sessions and user count. 

What went wrong?
We started seeing a drop in customer sessions, user and revenue from 12th of Nov on Google analytics. We checkout our internal systems and noticed no real drop in traffic or revenue.
We see that Google analytics is particular reporting loss of traffic on Windows 70.0.3538.77. I would expect the traffic to transfer to 70.0.3538.102 but that doesn't happen. 
It makes me think if analytics tracking is regressed on 70.0.3538.102. 

We have had no Javascript changes on the website. There are no unusual JS errors or fatals. 

Did this work before? Yes 70.0.3538.77

Chrome version: 70.0.3538.102  Channel: n/a
OS Version: 
Flash Version: 

It could be simply that customers are not migrated to the new Chrome yet but then I can't explain the drop in metrics for this particular customer segment. Any help?