Civil 3D corridor slope patterns disappear after exploding

If you use a custom slope pattern style that includes a block in its definition, the block disappears after exploding the drawing, see images below.

Before exploding:

After exploding:

To fix this issue, set the block property Scale Uniformly to No in the block definition:

For more details, watch the following video:

Note that this solution does not work for grading objects as shown in the video above.