Andrew,

Seen in al previous versions that I know of.
To recreate and merely as an example:
With:
- A polyline entity on a layer 'polyline' (notLocked - notFrozen - Visible)
- A hidden layer 'exploded' (notLocked - notFrozen - notVisible)

- Select the polyline .. DP .. XP >> duplicated polyline explosion in selection.
- Set the selection its layer to 'exploded'
by a double click in the Layer List or by Property Editor.
- Hide layer 'polyline' by toggling its visibility.
- Unhide layer 'exploded' by toggling its visibility.

The explosion is still in a dark red color.

Workaround: TA & TN

Regards,
CVH