Assertion failed! - in function 'getblueprint_at_point' - in function 'fetch_blueprint_at_point'

The auto wall function when building a second floor is bugging when I have a hole in floor for stairs to go up into next floor. Attached is crash code and screen shot of building. Also player id i f4196e9e-b101-11e5-818d-fcaa149968b1.

 release-491 (x64)stonehearth/services/server/build/build_service.luac:222: assertion failed!stack traceback:
	[C]: ?
	[C]: in function 'assert'
	stonehearth/services/server/build/build_service.luac:222: in function '_get_blueprint_at_point'
	stonehearth/services/server/build/build_service.luac:225: in function '_fetch_blueprint_at_point'
	stonehearth/services/server/build/build_service.luac:230: in function '_fetch_column_at_point'
	stonehearth/services/server/build/build_service.luac:231: in function '_add_wall_span'
	stonehearth/services/server/build/build_service.luac:199: in function 'visitor_fn'
	stonehearth/lib/build_util.luac:270: in function 'grow_walls_around'
	stonehearth/services/server/build/build_service.luac:199: in function 'grow_walls'
	stonehearth/services/server/build/build_service.luac:189: in function 'cb'
	stonehearth/services/server/build/build_service.luac:304: in function 'do_command'
	stonehearth/services/server/build/build_service.luac:189: in function <stonehearth/services/server/build/build_service.luac:188>

Hey there @Prophit, welcome to the Discourse! Thanks for the report.

release-519 (x64)
stonehearth/services/server/build/build_service.lua:1084: assertion failed!
stack traceback:
	[C]: ?
	[C]: in function 'assert'
	stonehearth/services/server/build/build_service.lua:1084: in function '_get_blueprint_at_point'
	stonehearth/services/server/build/build_service.lua:1100: in function '_fetch_blueprint_at_point'
	stonehearth/services/server/build/build_service.lua:1117: in function '_fetch_column_at_point'
	stonehearth/services/server/build/build_service.lua:1135: in function '_add_wall_span'
	stonehearth/services/server/build/build_service.lua:982: in function 'visitor_fn'
	stonehearth/lib/build_util.lua:697: in function 'grow_walls_around'
	stonehearth/services/server/build/build_service.lua:981: in function 'grow_walls'
	stonehearth/services/server/build/build_service.lua:953: in function 'cb'
	stonehearth/services/server/build/build_service.lua:1430: in function 'do_command'
	stonehearth/services/server/build/build_service.lua:952: in function <stonehearth/services/server/build/build_service.lua:950>

Hey there @Runsis, welcome to the Discourse! Can you provide a few more details on what was going on when you got this error? When exactly in the design process did this appear?