The destination list or library contains folders with Managed Metadata columns which are not supported by Insane Mode

Symptoms

When attempting to copy an item, Sharegate displays the following warning in the "Migration Report":

The destination list or library contains folders with Managed Metadata columns which is not supported by the Insane Mode.

Due to a limitation in the Office365 API, folders that have Managed Metadata columns on them cannot be copied when using the Insane Mode.

There are two options available to you if you need to copy the Managed Metadata on a folder:

Run the copy using the Insane Mode, then add the Managed Metadata manually after Sharegate has completed the copying process.
Use the normal mode to copy Lists or Libraries that use folders which have Managed Metadata, and then complete the copy with the Insane Mode.