Loosing line type when exploding a block

I have an imported block that I want to explode.  However, when I use Explode, the dashed and center lines types are converted to continuous lines.  

I've tried several options for creating the block drawing:
1. All lines are in Layer 0
2. Moved the lines to another named layer.  
The default line type for Layer 0 and the named layer were "continuous"

I've tried several options for Importing the block:
In the Pen toolbar, I've selected line type "by layer", "by block" or "Dashed"
1. If I then explode the block, all lines are continuous, for "by layer" or "by block".
2. If I explode the block imported with the "Dashed" selected in the Pen Toolbar, then all the lines are dashed.

FYI, I'm importing 3D projection drawings of components and want to split the drawing up so I can move each of the projections to various parts of a larger drawing.

Am I missing something, or is this an unintended (or perhaps, intended!) consequence in the coding?

Thanks in advance.