I'm fighting a similar thing currently. Got the latest FreePascal/Lazarus trunk/trunk checked out this morning using fpcupdeluxe, but this has happened for weeks now. I've got those UsageCustomOptions in place.
When I let the Lazarus UI create the .app bundle folder for my binary, macOS tells me the app would be designed for 10.14, while I only run 10.13.6. If I run the executable directly, it works fine.
This is even valid for the Lazarus.app created by fpcupdeluxe.
It's getting spooky... I copied an older app bundle and modified it completely for the app I was testing. Adjusted icon, Info.plist entries, etc.. Runs fine - until I rename it, or compress/decompress it, then macOS again tells me it's incompatible. Same message appears on other Macs, so it's not strictly a local curiosity. A simple "touch" to the .app and the Info.plist renders the bundle incompatible.
Has anyone experienced similar (including Lazarus.app and stock created new app bundles not working)? Any workaround?