CBT + Multiple "Drop-down hotspot" Link Styles = Broken Content

RoboHelp 2017, all updates installed.

Created multiple hyperlink styles, specifically for drop-down hotspots, so I could generate output similar to this:

This project also uses conditional build tags, so we can generate public and private content. When I generate the public version (exclude proprietary and confidential info using CBTs), the drop-down links no longer work. All the links work if I don't exclude any content. Note that while the styles in the example image above take advantage of the Twisties option, I left those out when troubleshooting (and in the repro steps below) and the issues still existed.

Steps to Reproduce

1. Create new RoboHelp project (I did this after discovering the issue in an existing project to help eliminate other potential failure points/causes - from my CSS, etc.).
2. Edit/open "First Topic" in the project.
3. Create new conditional build tag called "confidential".
4. Duplicate existing "Drop-down hotspot" hyperlink style in default.css and name it "copyofdropspot".
5. Select some plain text in "First Topic" and apply "confidential" build tag to it.
6. Select some other plain text and insert a drop-down. Allow default hyperlink style "Drop-down hotspot".
7. Select different plain text and insert a drop-down. Re-select that text and apply/force the "copyofdropspot" style to it.
8. Save the changes and open/edit Responsive HTML5 SSL output config.
9. Create a simple build expression that excludes "confidential" build tagged content.
10. Generate the output and view "First Topic".
11. The excluded text is properly and correctly excluded.
12. Test the drop-down link formatted with the "Drop-down hotspot" style. It functions properly and correctly.
13. Test the drop-down link formatted with the "copyofdropspot" style. Nothing happens when the link is clicked; that is, the text in the drop-down isn't displayed even though it should be.

Thoughts or suggestions?