Absolutely is still read. Previous question regarding display of add-to-cart quantity was already addressed and could have been accomplished in other ways as well.

As to this issue, I've looked through the code and nothing stands out as the cause, but still need to try to replicate the issue.

If I understand correctly the setup is: product has a single option name and that option name has a single option value. The option name is setup to use the PAG option.

In the above configuration, you're saying that only a radio button is presented and not the PAG option.

Come to think of it, the way that the attributes.php file is setup, this seems like a ZC overrides the currently considered action situation. And the goal would be to override that "natural" action and allow operation to then continue back to show the PAG option.

For your store, could modify your includes/modules/YOUR_TEMPLATE/attributes.php and remove this entire section:
Code:
// dropdown menu auto switch to selected radio button display
                  case ($products_options->RecordCount() == 1):
                  if ($show_attributes_qty_prices_icon == 'true') {
                    $options_name[] = '<label class="switchedLabel ONE" for="' . 'attrib-' . $products_options_names->fields['products_options_id'] . '-' . $products_options_value_id . '">' . ATTRIBUTES_QTY_PRICE_SYMBOL . $products_options_names->fields['products_options_name'] . '</label>';
                  } else {
                    $options_name[] = $products_options_names->fields['products_options_name'];
                  }
                  $options_html_id[] = 'drprad-attrib-' . $products_options_names->fields['products_options_id'];
                  $options_menu[] = zen_draw_radio_field('id[' . $products_options_names->fields['products_options_id'] . ']', $products_options_value_id, 'selected', 'id="' . 'attrib-' . $products_options_names->fields['products_options_id'] . '-' . $products_options_value_id . '"') . '<label class="attribsRadioButton" for="' . 'attrib-' . $products_options_names->fields['products_options_id'] . '-' . $products_options_value_id . '">' . $products_options_details . '</label>' . "\n";
                  $options_comment[] = $products_options_names->fields['products_options_comment'];
                  $options_comment_position[] = ($products_options_names->fields['products_options_comment_position'] == '1' ? '1' : '0');
                  break;
At least until a more suitable standard solution is developed. It's a bit of a "hack", but would directly accomplish the desired task.

Ps. If there are hashtags (#) in the above, I apologize in advance. The content was directly copied from github and sometimes spaces turn into hashtags when I do that. I don't have an option to paste any special way at the moment to possibly remove and it would take a while to correct them after posting.