This crash (without a crash report, or I can’t find it) happens when you have connections from one node to the same node with zero weight. To reproduce it, you can take the Pathfinder example and add this line to the flipSelectedSquare function:
local function flipSelectedSquare()
local node = graph:nodeWithXY(cursor.x, cursor.y)
node:addConnectionToNodeWithXY(cursor.x, cursor.y, 0, true)
And, after that, run the example and flip a square a few times on the found path.
It happens on MacOS, SDK 3.0.1
Yes, it is a strange corner case; yes, not so many people face this, but I assure you - debugging this problem is a pure burning hell.