OK, so here is what needs to be addressed in a future update of Multiterm 2017. This was actually a question I posted on another forum and Paul Filkin confirmed it was a bug and may be resolved in a later update, but that I needed to put it here just to make sure.

I created a termbase with an entry-level picklist field named "subject field". I added several subjects to this field such as "General, Engineering, Medical", etc. Now, whenever I add a new term in MultiTerm 2017 and click on the "add a new field" and then select "subject field" to assign one of these to my newly-added word, the first one, i.e. "General" is automatically selected as the subject field for my term. I have to click on the dropdown menu on the right hand side of the word "general" to open the picklist, select the right subject field, and then click the tiny x on the right of "general" to remove it.

And here is Paul's response:

I see exactly what you mean now. I created a termbase exactly as you explained and when adding a new term with the default view it isn't very intuitive as you first have to add the terms first, and then the add new field at entry level becomes available for you to add the new field. At this point when you select it the first in the list is added and you have to hover over the edit button to select a new one and then remove the first one. I have a feeling this may be getting addressed in a later release, but Luis Lopes will be able to confirm.