For those who want a workaround: I’ve published the above script at GitHub - macfreek/homey-scripts: Miscellaneous scripts for interacting with a Homey smart home controller
To get started, it now has a README. That said, I have not spend time duplicating the effort of Flow Checker. With HomeyScripts (another app), you can run the script, and for example return the number of broken flows. That said, I don’t see an easy way to report which flows are broken with HomeyScripts. So personally, I’ll just run this script locally whenever I think something is wrong, or after I’ve replaced devices. Let’s hope AtHom will fix the issue reported by Martijn. Much easier for everyone.