Doubling terms when importing they

Hi friends.

I'm testing the Taxonomy Manager module. The module and the idea are very good and can greatly assist admins.

But I encountered a problem and I need help.

I'm working on a new project, which for now is on localhost. For this project, we need to create a relationship with cities and states of a country. There are over five thousand cities.

The idea is to create the parent terms manually and import the child terms using the MASS TERM IMPORT.

But during the import, some terms are being processed in duplicate (see picture).

In the example image, DF was copied into the SP, along with all their children terms. The new child terms was imported to DF term, and the DF parent term was copied with their child terms into

This happens often and we had to delete the terms several times.

Something is wrong. What can be? This is a bug?

Tks.