Cryptic Vector mixup and broken Cast

I experience two different behaviours with the same logic in the blueprints. Simple gravity simulation using LineTrace.

Result when playing in editor:

Result when simulating:

I’m unaware if there is something different about simulating, but this cast fails when simulating.

The cast succeeds when Playing in Editor.

Note that reproducing this happens when I delete the scene actor and place a new one. I also have no idea what triggers it.

Everything works fine if played one a separate window. I also don’t know how or why it breaks, in other words whenever it got working it just got fixed on its own, without me doing any adjustments to anything at all.
My guess would be that maybe I’m doing something wrong when getting the UP vector, however, this has occurred with every possible way of getting a vector, be it from a worldRotation or specific component or actor. All of them change direction at some point or another and force me to edit the blueprint and swap out the vector, until it breaks again.
I put this in bug reports since honestly I don’t even know what to ask.

Edit: I redid everything in a new project 1to1, I’m not able to reproduce this. Bug or not, it’s hopefully dead.

Hello, I re-created your trace and did not see your problem.

I noticed that the origin of your trace is “Scene Component ref” - deleting the scene actor and placing a new one may be clearing this reference.

Hope that helps, let me know if you can get a good repro!

You mean the Actor or the Component? I didn’t delete any components at runtime. Deleting the Pawn in the level and placing a new one didn’t solve it either. Play in separate window fixed it, simulating broke it again (i think it has something to do with simulation).

Funnily enough, I’ve tried box and capsule with the same logic and haven’t experienced the issue with those traces. I’ll try to reproduce again, but I have no idea what could be the trigger. If by some magic it happens again, I will make a video and capture everything that I can think of creating this problem.

I’ll holler if I get it. Thanks for looking into it.

I was referring to the variable in your BP - just wasn’t sure how you had your variables set up.

Marking as answered - just reply to this thread to re-open!