When attempting to copy an item, the app displays the following warning in the Migration report:
The destination list or library contains folders with Managed Metadata columns which are not supported by the Insane Mode.
Due to a limitation in the Microsoft 365 API, folders that have Managed Metadata columns cannot be copied when using Insane mode.
There are 2 workarounds available to you if you need to copy a folder that has a Managed Metadata column.
Add the Managed Metadata column manually
First, run your copy using Insane mode. When ShareGate has finished the migration, add the Managed Metadata column to the folder manually.
For more information, see the Microsoft article Introduction to managed metadata - Applying metadata.
Use Normal mode
Managed Metadata columns can be copied using Normal mode. You can use Normal mode to copy the lists or libraries that use folders with Managed Metadata columns, then complete the rest of the copy using Insane mode.
For information on how to adjust from Insane mode to Normal mode, see Migration speed.