This error is typically experienced when other applications using different samples rates to your Pro Tools session try to use the ZED-R16 to pass audio.
Because the ZED is capable of changing sample rates on the fly, Pro Tools reports this back as an ASIO change and requests a restart.
There are a couple of ways to resolve this error:
1) Do not assign any other applications or operating systems to the ZED, only Pro Tools.
2) If the ZED is required to be used for OS and other application sounds, ensure system sounds are disabled in the OS and also check that other applications, such as antivirus, also have their sounds disabled.