This is a bug with DataONTAP PSTK 3.3 which is bundled with WFA3.1. You have 3 choices:
1. Wait for NetApp to fix this bug in PSTK and WFA bundles it along with the next WFA. It will take months.
2. Modify your code to handle this exception. I think command is getting executed sucessfully at cluster end but still PSTK throwing error. You can handle this exception in your code. This would need you to modify all the commands which are having such issues.
3. If you are satisfied with PSTK3.1 which was with WFA3.0 then I suggest you modify the DataOnatp PSTK on your WFA3.1 to the PSTK version 18.104.22.168 as given in How to upgrade or modify the DataONTAP Powershell Toolkit(PSTK) in WFA. No need to modify any code anywhere and it will work seamless. You can upgrade your PSTK later on when the bug gets fixed.
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