The last commit from MDL-42887 removed one too many CSS rules from bootstrapbase.

The only difference between the rules for bootstrap base and standard is that in the collapsed view - standard should have a margin beneath the field elements - bootstrap already has this accounted for - so should not have this rule.

In the commit f05974496897067d797a3113857833d3032d08cf I accidentally copied this rule from base to bootstrapbase.

The end result is that on clean theme - there is an extra 6 pixels between the form elements in the collapsed view.