Vertical button style radios/checkboxes bottom label margin not removed

Created by: tmorehouse

• Bootstrap V4.0.0.-beta.2
• Operating system and version (any)
• Browser and version All
• Reduced test case https://codepen.io/tmorehouse/pen/BwEpOr

When using button style radios or checkboxes in vertical mode, the label margin-bottom is not set to 0 causing spacing issues between the "buttons":

Expected behavior: That the bottom margin be set to 0 for the labels, as would be for regular buttons in a vertical button group.

Workaround:

.btn-group-vertical label.btn {
  margin-bottom: 0;
}

or manually setting class mb-0 on each label.btn