Summary
Currently, the product specification selection box of the page accountname.myvtex.com/admin/products/new/ has a faulty behavior when attempting to select a value for a product specification.
When the user attempts to choose a value, sometimes, the input below is selected instead.
For instance, you have 2 options, color and size. Upon clicking on color, you, sometimes, have size selected instead:

Simulation
This is an intermittent case, hence, it is quite hard to consistently replicate.
Anyhow, to do so, you must go to the aforementioned page and choose the (+) add variations function.
Upon doing so, a popup will appear with the given dropdown menu that has the faulty behavior. Trying to select a value might return the data below in its place.
Workaround
Using the APIs or even simply changing the admin language will yield positive results.