Hi friends,
I have noticed an issue in Dynamo 2.6.1 that appears to cause an incompatibility with the LunchBox node Curves.ShortestWalk. The 2.6 Dynamo release notes indicate there was rework to PolyCurve intersections and I assume other related stuff under the hood that could be affecting this. Here is a screenshot of the warning message for reference:
All the best,
Anthony