WiX patching not updating files correctly

My "admin-image" style WiX test patches are failing to update the existing installation correctly. When using msiexec /lx, I get the following information related to patching "fi_executable.exe":

MSI (s) (88:E0) [12:32:41:716]: Baseline: Patch {E244BAC8-7E62-4406-889B-4B67A4EA7369} modified fi_executable.exe with full-file update.
MSI (s) (88:E0) [12:32:41:716]: Baseline: First patch for fi_executable.exe, saving native info.
MSI (s) (88:E0) [12:32:41:716]: Baseline: fi_executable.exe version for baseline at patch Native: 6.0.5803.11, 1033, 53840.
...
MSI (s) (88:E0) [12:32:41:716]: Baseline: fi_executable.exe version for baseline at patch {E244BAC8-7E62-4406-889B-4B67A4EA7369}: 6.0.5830.99, 1033, 47104.
...
MSI (s) (88:E0) [12:32:41:763]: {E244BAC8-7E62-4406-889B-4B67A4EA7369} File: fi_executable.exe ValData: 6.0.5830.99 1033 47104
...
MSI (s) (88:E0) [12:32:41:763]: Native File: fi_executable.exe ValData: 6.0.5803.11 1033 53840
...
MSI (s) (88:E0) [12:32:42:543]: The file represented by File table key 'fi_executable.exe' has no eligible binary patches

So even though the version number is changing, and Windows Installer notes that the patch modifies the file, Windows Installer is not recognizing that there should be an update to the executable.

Why?