The log file says that thinreg worked for the exe file (when it was first synced), but was skipped for the dat file (which is normal). Are you using non-persistent VDI desktops by any chance, and/or roaming profiles? There is known issue that the thinreg 'database' is part of the user's roaming profile, which can cause issues (see VMware KB: Using VMware ThinApp packages with non-persistent Floating Pools in VMware Horizon Vie...). Maybe you could also check to see if anything exists for the app under %AppData%\Thinstall\Unregister, before the Horizon ThinApp agent attempts to sync it.