@v-bacao-msft
Hi,
The problem is that it only returns a single metadata term - not all that are present in the list.
The 'Create File' related actions are within an 'Apply to each' action and works as expected for all other file properties:

However, when I try to add the Managed Metadata column values, it further automatically wraps each output in a further 'Apply to each' action which I believe is causing the problem:

Hope this provides enough information for you to help advise how this should this be configured.
Many thanks,
Mike