Title behaviour different between TextField and DropdownField

<%- if @topic_view.topic.tags.present? %>
<%= t 'js.tagging.tags' %>: <%- @topic_view.topic.tags.each do |t| %> <%= t %> <%- end %>
<% end %>

Silverstripe Version: 4.5

Why is there different field title behaviour between DropdownField and TextField.

This

$fields->addFieldToTab('Root.Main', TextField::create($field));

or, this:

$fields->addFieldToTab('Root.Main', TextField::create($field, null));

Render the field table as expected. IE a field of SomeField has a title of Some field.

Doing the same with DropdownField doesn’t create a field title like that, it just uses the field name of SomeField.

$fields->addFieldToTab('Root.Main', DropdownField::create($field, null, $this->hours(21600, 43200))->setEmptyString('Select...'));