Display differences for same objects doesn't make sense

[BBP-Arch]

ACA2011

Two AutoDesk AEC Mask Blocks from the Design Center have been inserted into my reflected celing plan, attached to the AEC Ceiling Grid.  One block is a 2x4 Fluorescent Light and the Other is an Air Supply Diffuser. They're both listed as AEC Maskblock refs. However, when I change the display from Reflected to Medium Detail, the diffusers go away and the lights remain...why? I've looked at the definitions and they are the same, the Display Manager appears correct...not sure the deal here...any ideas?

Thanks in advance,

Scott

[David_W_Koch]

Nested inside the Mask Blocks are Multi-View Blocks which provide the graphics portion of the Mask Block.  Without checking, I believe that the out-of-the-box lighting fixture Multi-View Blocks are now set up with the view block assigned to a Display Representation that is on for both the regular plan and the RCP Display Configurations (based on requests from residential folks, who often do not have an RCP, and want the light fixtures to show in a regular plan), while the Multi-View Block for the HVAC diffuser has a view block that is assigned to a Display Representation that is only on for the RCP Display Configuration.