Yo MieskoZ, I’m assuming this was fixed since I didn’t have any problems when I tested it. Can you see whether the same bug is also in the Get Path Length node as well? I’m getting pretty much the same problem just with the path cost node instead.
I’ve put it in a separate post here: Get Path Length/Cost is 0 - Programming & Scripting - Unreal Engine Forums to report it as a bug, however since you seem to have found a solution for it I thought I’d post here as well.