Intermittent track matte glitch

Operating System Info

Windows 11

Other OS

No response

OBS Studio Version

Other

OBS Studio Version (Other)

27.1.3 and 27.2b2 and b3

OBS Studio Log URL

https://obsproject.com/logs/6N0t2DrV608U-uia

OBS Studio Crash Log URL

No response

Expected Behavior

Matte stinger transition should take you smoothly from Scene A to Scene B.

Current Behavior

Matte stinger transition intermittently flickers with a 1 (or a couple?) frame from Scene A (I think) after the transition from scene A to scene B completes. This is separate from the issues experienced when spamming scene changes.

This seems to be the opposite of the issue reported in #4886 where they reported the flicker happened before the transition if I'm reading their "Current Behaviour" right. Even though other videos seem to show the same issue I am seeing.

It is possible what they saw as the glitch showing before the transition was because of the speed at which they were switching (it actually followed the last switch rather than preceeding the next) but its impossible for me to say.

Steps to Reproduce

1. Create multiple scenes
2. Add color source to each scene to make the flicker more obvious
3. Add multiple Window Captures (any mode should work), elements etc to each scene.
4. Add a stinger, select 'Matte_Transition_08.webm'
5. Transition between your scenes

It seems (at least for me) its more common on scenes with a number of elements but does not correspond with something visual like an encoding or rendering lag spike. I also note it seems to be more reliably reproduced on the first switch to a scene, subsequent switches don't seem to exhibit it as reliably?

Anything else we should know?

It seems limited to track matte's for me... If I switch to fade etc it no longer occurs.

I'm getting an example video and will upload as soon as I can.

Edit: Example track matte attached
Matte_Transition_08.zip

Start by reproducing the issue using the listed scene setup, the attached Matte_Transition_08.webm asset, and the provided OBS log. Compare track matte transitions with fade transitions and check whether the intermittent post-transition frame appears, especially on the first switch to a scene. Done means the flicker is reliably explained and no longer occurs without introducing a regression.