Wipping out graphics with black background in text

OK this one is still bothering me.  I have a font set up with a black background in hopes that it will wipe out anylines behind it.  In most of my files it does not work but in a couple of the files it works.  I have attached both files in a .pzip.  If anyone has any ideas please let me know.

hmmg_82s_A60-23-M3112.dgn works great

hmmg_82s_A60-23-M3111.dgn does not wipe out line work

So far I can not find any differences between the two.

 

Thank you

John Matthews

Black Background.pzip