can't save label name in custom taxonomy

Keep trying to add something to "Choose From Most Used" label, but instead it replaces what I've written with the text I added into the "All Items" label. Its a non hierarchical field, so not sure why its not saving.

Also trying to choose from 'most used tags' for this field within my custom post type and although I've added a bunch of fields already, none are showing up.

Support access granted. MODULES is the name of the custom post type.