MacOS by default goes the extra mile and attempts to unbundle our system bundle files used to deploy Zone processor firmware and WebApp updates.
There should be no problem when downloading the system.bundle file from the software page of the website as the single file will be untouched by MacOS.
When the bundle file has been zipped for sending via email or some other transfer mechanism, MacOS will automatically unzip the file, then also unpack the bundle (it is actually a tar file containing all the folders and assets needed to update the unit. It is not necessary to do this and actually makes the update process more complicated and error-prone).
To prevent MacOS from unpacking the bundle, please use Spotlight Search to locate the Archive Utility in your system utilities folder.
Go to Edit settings and turn off the setting called "Keep expanding if possible".