Hope this helps you investigation of the issue...
Deform Timeline optimization fails depending on Track application order
We are experiencing an issue where the visual result of an animation differs depending on the order of the tracks being applied.
Specifically, there seems to be a conflict between the Deform Timeline and the Attachment availability across multiple tracks.
Suspected Cause (Technical Investigation): Without having investigated the full runtime source, the issue appears to stem from an optimization within the Deform Timeline.
The Logic: It seems the Deform Timeline attempts to bypass calculation (early return) if it detects that an attachment is not currently present.
The Problem: This assumption holds true if all keys are on a single track. However, when using multiple tracks, the order of application becomes critical.
Scenario A: Track 0 animates the Deform; Track 1 animates the Attachment.
Scenario B: Track order is reversed.
Because the "Early Return" check happens before the second track applies the attachment (in specific track orderings), the deform is skipped incorrectly.
This causes inconsistent animation states and visual glitching when layering animations.
We have encountered similar issues with this specific logic in the past.
