Disable wall "merging"?

[madcowscarnival]

I'm trying to create a drawing for as-built conditions.  One side a framed wall is set on a concrete stem wall ~80" above grade.  About half way along its length the concrete stem wall drops to 36" above grade.  CA works fine when one side is pony wall conditions and the next is full height framed.  But, as soon as I change that next wall to a pony wall it automatically merges both walls and makes the lower wall height the same along the full length when I close the dialog box.

 

I'm sure this is something I can turn off, but I don't know "what" to call it for a search.

[PitMan71]

Default Settings (Wrench Icon) > Wall > General Wall > Uncheck "Auto Merge Colinear Walls"