The format painter does not always copy styles correctly from one object to another. The padding inside a field is often dropped. It seems like the theme gets corrupted somehow. New fields are dropped in with the normal style, but using the format painter causes styling problems.
Steps to reproduce the problem
Use the format painter to copy the style of one field to another.
The style is copied.
Some of the style is copied, but all padding in the field is dropped (even if the style is the same on both fields to begin with).