[Engine] Animation playback for "constant" key frames changed behavior when Roblox released the curve editor

[Quenty]

Hello,

We have this following issue. Sometime between 8/8/2024 and 8/29/2024, roblox changed how exported none interpolation worked, so instead of moving when the keyframe fires, it now waits for the following keyframe to move.

Before/Preview (happens in moon animator + in roblox clip editor)

After (when playing the animation):

The attached file has my moon 2 animation save in the “Original” car. what plays back through moon was the previous, expected behavior. the “Exported” car is what plays back live when you run the game.

notes

• This is not a moon animator export bug, the engine changed how the “none” interpolation worked.
• Roblox editor also works this way, and the behavior changed. (In the editor, this is known as “Constant”
• The animation is not converted to curves.

Another scenario, in Roblox studio editor:

This is likely due to DFFlagAcceleratorUpdateOnPropsAndValueTimeChange

A private message is associated with this bug report

[drewbluewasabi (Drew)]

Bump, this is making it hard for me to create animations with the built-in animation editor because the preview is not accurate to the final product.

This bug is also causing confusion;

Constant style animation skips the first frame

I’m not sure if this is the right place to post this, but I couldn’t find an animation support category so here goes. I’ve made a few placeholder animations for a fighting system. All of the animation use constant style keyframes because I like how it looks. When playing the animation, the first frame gets skipped and the last frame is kept on extra to make up for the time lost by skipping the first one. The animation priority is Action4 and all other animations are stopped from playing befor…

AnimationEditor:

Runtime Playback:

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Repro file:
ConstantEasingRepro.rbxl (75.6 KB)
Upload the “FloatDrop” animation, then paste the ID into the Animation located under Workspace.