Because I thought this was a platform error not related to my site, I submitted a ticket on this issue this morning. Support cancelled it automatically because I was in Access Now and said they were sending the message to the community. I've been watching for it all day in the community and have not seen it. Therefore, I'm posting it again here.
When I view any page in Big Data Analytics I get this error message with a red background across the top of every page if the platform is set to Ezoic or Old Site.
A Segment containing a 'Tech Platform' filter is not allowed when the selected global platform is either Ezoic Platform or Old Site
In the details section below the timeline I get "Internal Server Error."
I can set the platform to All Platforms and the message goes away.
I've never seen this issue before, even though I usually watch my stats with it set to Ezoic only.