Actors Not Ticking after Streaming Sublevel

After loading actors using a level streaming Volume, those actors do not tick.
If the streaming level is unloaded and loaded again, the loaded actors behave normally.
Loading actors using the LoadStreamLevel Node in blueprints also causes no problems.
Is this a bug or is it intended behaviour?

The steps I took to recreate this problem:

Create a new Project (I used the VR Template)

  • Create a persistent level with two
    sublevels, A and B

  • Set A to be Always Loaded, and Set B
    to Blueprint

  • In each level add an actor that prints to
    log with each tick

  • Add a streaming volume for level A

  • Create an actor with box collision
    that calls LoadStreamLevel for Level
    B when OnbeginOverlap is called

  • Run PIE and try entering each volume


I have reproduced your issue, and have entered a bug report, which you can track using the link below:

Thanks for your report.

Have a great day

Hi Sean

just ran into this problem last week and it’s quite a critical bug for our application.
How can I access the fix commit referenced in the Bug Report you linked to?
Is it already available to the public?

Thanks for your help.

Best regards

Edit: As a bandaid fix I manually register the tick functions now instead of relying on Unreal doing it automatically.

Hey mvddreher,

Unfortunately that commit is not available for the public yet. Keep an eye on the link to the public tracker, as it will turn the CL for the commit into a hyperlink which you can then use to access the commit.

Have a great day

I’m having this in 4.18 when I stream a level in using the Load Stream Level node.

Only happens if I follow up with a FlushLevelStreaming node, which I’m doing because I need a blocking load and that’s the only way to get it.

Here’s how you would repro - where the level streamed in (here InFlux_Beach) contains the actors that aren’t ticking.

I have this as an issue as well. A game breaking bug, suprised irs not come up earlier and has been about since 4.15. Is it fixed for 4.19?

Hi sean, This seems to be happening in 4.19.
Steps to reproduce:
1 empty persistant volume
2 floor in level streaming volume A
3 Actor placed in level streaming volume B, that has several level streaming volumes, one of which is a load, and after a viz and laod.

PIE or build, player starts play, walks over the ground in A. into level B’s loading level streaming volume. and then into level B’s level viz volume. Actor in B does not tick

But, leaving b and re-entering several times makes B tick.

Suggesting activation of ticking is not perfectly synchronized with the action of loading actor maybe?
not this bug is prevalent tin an open world area with several levels for lightning and detail objects loading and unloading.