Road tool Engine Error

occasionally the road menu becomes disabled this way.
Steps to reproduce:

  1. place a template down
  2. erase slightly oversized road
  3. replace part of the road that wasnt oversized

Expected Results:
road is planned
Actual Results:
road menu shuts as soon as it’s clicked

release-851 (x64)[M]
stonehearth/services/client/building/road_tool.lua:78: bad argument #1 to ‘upper’ (string expected, got nil)
stack traceback:
[C]: ?
[C]: in function ‘upper’
stonehearth/services/client/building/road_tool.lua:78: in function ‘_set_cursor_color’
stonehearth/services/client/building/road_tool.lua:31: in function ‘__init’
radiant/modules/commons.lua:23: in function ‘RoadTool’
…services/client/building/building_client_service.lua:967: in function ‘?’
…services/client/building/building_client_service.lua:936: in function <…services/client/building/building_client_service.lua:929>

Version Number and Mods in use:
851 version number
Templates (Town center)
Green Mesa Biome
Hearthlings of Many Faces
Locks of Many Hair
Miner Profession