"ERROR: [1663-31-80-80131501] Unable to migrate delegation for resource" (4287959)

When  trying to migrate Resource Mailbox with delegations. MigrateResourceDelegation=1 parameter is also used. You see the following error:

ERROR: [1663-31-80-80131501]Unable to migrate delegation for resource 'resourcename@domain.tld': 
Source: DellSoftware.PowerShell.Core 
Description: There were errors in loading the format data file: 10:21:25 Microsoft.PowerShell, , C:\Users\Username\AppData\Local\Temp\1\tmp_filename.ps1xml :

File skipped because of the following validation exception: File C:\Users\Username\AppData\Local\Temp\1\tmp_filename.ps1xml cannot be loaded because the execution of scripts is disabled on this system.

Please see "get-help about_signing" for more details.
Message: Unknown error 0x80131501

Error 80131501

The Execution Policy had been set to Unrestricted