Attempting to use UAT on Windows to remotely create a standalone build of a project for Mac fails in 4.19. The error message indicates that it cannot find part of the path to the project's Info.plist file, but the path that is being used is incorrect. Instead of D:\Contents\Info.plist, the correct path should be D:\Unreal Projects\Current Issues\TESTMacBuild\Intermediate\Staging\TESTMacBuild.app\Contents\Info.plist
Attempted to test this in 4.18.3, 4.20.2, and 4.21, but each of those versions failed with a different error.
This repro requires that Mac files are present locally. This can be accomplished by running the following commandline: Setup.bat --include=Mac
The build fails with an error similar to the following: ERROR: System.IO.DirectoryNotFoundException: Could not find a part of the path 'D:\Contents\Info.plist'.
The build completes successfully.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-64148 in the post.