Assertion failed crash after using exported Sequencer animation in FPS character

DoubyBear
Thu, 10 Jul 2025 09:06:25 +0000
Programming & Scripting

I’m working on first-person animations in Unreal Engine using Sequencer. After creating the animations in Sequencer, I export them as Anim Sequences and then use them in my Animation Blueprint for a first-person character.

When I play the game in the editor (PIE), my character sometimes crashes the engine with this Assertion failed: AllDisabledTickFunctions.Remove(TickFunction) == 1
[File:D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\TickTaskManager.cpp]
[Line: 1806]

This crash does not happen if I remove or close the original Level Sequence or Sequencer asset.

So far I suspect:

There might be a leftover TickFunction or binding from the original Sequencer.

The exported animation may still carry curve tracks (e.g., visibility, enable, transform).

The Animation Blueprint or SkeletalMeshComponent might be receiving conflicting state from the old Sequence.

What I want to know is:

What causes this AllDisabledTickFunctions.Remove(TickFunction) == 1 error?

Is there a best-practice way to export and clean Sequencer animations for use in first-person characters?

How can I avoid this crash in future animation workflows?

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