When I try to build my primary target using Flare 2021r2 or newer, I get an error message that says "Build failed: An item with the same key has already been added." This happens consistently, with every build. I am building an HTML5 output.
The messages in the log file indicate that it is always the same help topic. I have tried clearing my output folder before building, deleting the referenced topic from the project, deleting the Analyzer, Output, and Users folders, deleting the Flare folder in the registry editor, and deleting the Flare folder in C:\Users\<username>\AppData\Roaming\MadCap Software.
I've spoken with MadCap support, and they think this is related to an existing bug (#171817). The bug they referenced occurs when you build a target with two or more topics that have similar names, and the option for "Replace reserved characters with underscores in filenames" (Target Editor > Advanced tab) is enabled. My project imports files from several localized child projects, and child project are exact duplicates of the parent projects (file structure and file names are the same, but the topic content is localized). So there are file names that are exact matches, but the option to "Replace reserved characters with underscores in filenames" is not selected in my project, and the issue is only present in Flare 2021r2 or newer. Older versions of Flare can successfully build the same target with no issues.
Has anyone else encountered this issue, or does anyone have any suggestions for troubleshooting or potential workarounds? Any help would be appreciated.