Issue appears in Calcite version 1.0.7 (and earlier versions).
I'm noticing a downward vertical offset of the calcite-dropdown list when it is put inside a calcite-block with a heading property.

When the block heading property is removed, the list appears in the correct position directly below the list.

Here is a Codepen to replicate the issue: https://codepen.io/fcbasson/full/KKxMLgJ