For the original "Duplication issues in RH 2019 Frameless Output" post, I marked Peter Grainge's answer as correct. I have some additional info to add.
Regarding the duplication of topic names listed in the "In This Topic" section, Peter determined that the duplication is occurring as a result of a heading style being applied to DropDown text. He said Adobe plans to include a fix for this duplication in the next release.
Our IT department told us we needed Windows Server 2016 for the server to properly display the frameless output. They set up a new test server for us. The new server resolved most of the issues I noted in the previous post.
We did notice differences between how Chrome and IE display the content. See image below:
Chrome appears to display the content well (duplication issue aside). IE does not display the "In This Topic" region. IE also appears to stretch some of the icons horizontally (almost as if forcing them to be "square"). The icons still work, but the "Print" icon in particular appears distorted, missing lines of pixels on the right and bottom edges.