Within Server 2016, I had issues adding the process exclusions via the Defender Add Exclusions setting page. (Folder and file exclusions were fine.) I also couldn't manually apply process exclusions directly within the registry (via regedit or GPO). Powershell resolve the issue, though:
PS C:\> Add-MpPreference -ExclusionProcess "C:\Program Files\Malwarebytes\Anti-Malware\MbamPt.exe"
PS C:\> Add-MpPreference -ExclusionProcess "C:\Program Files\Malwarebytes\Anti-Malware\mbam.exe"
PS C:\> Add-MpPreference -ExclusionProcess "C:\Program Files\Malwarebytes\Anti-Malware\assistant.exe"
PS C:\> Add-MpPreference -ExclusionProcess "C:\Program Files\Malwarebytes\Anti-Malware\malwarebytes_assi
PS C:\> Add-MpPreference -ExclusionProcess "C:\Program Files\Malwarebytes\Anti-Malware\MBAMWsc.exe"
PS C:\> Add-MpPreference -ExclusionProcess "C:\Program Files\Malwarebytes\Anti-Malware\mbamtray.exe"
PS C:\> Add-MpPreference -ExclusionProcess "C:\Program Files\Malwarebytes\Anti-Malware\MBAMService.exe"
Nice to have the exclusions added, even though I wasn't having issues beyond the system tray being absent. Many thanks to Porthos for the list!!!