?
My fault, I had forgotten about the shared TMP directory and was focused on the WRK and SRC ones. It appears then that building the same app but different workflows at the same time is not currently supported, but there are workarounds.
As an example, you could use a different environment (e.g. Integration2) for the patch workflow, then link/share all the action groups from Integration. If you were to then install a BuildMaster agent on the BuildMaster server (and add it via the Servers page), that agent would have its own set of temporary directories. All you'd have to do is update the "default server" setting for each action group in Integration2 to point to the agent server.