[Chris Wright]

is your gfx card supported for cuda?
By default, CUDA needs at least 768M video RAM
go to:
file-project settings-video renderer-is it greyed out?

[Chris Wright]

i didn’t see the question, but this might be helpful
https://www.videocopilot.net/products/the_bullet/

also, have you seen this?
https://www.youtube.com/watch?v=aqncOP7OzMg

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[Chris Wright]

I apologize for the long list of things to try, but the solutions are so varied, I had to list them in order of likelihood.

1.Disable Multiprocessing
2 update Adobe updates
3.your footage may have video/audio errors. Can you render to png image sequence? Or transcode in handbrake first
4. Use Adobe Media Encoder-instead of using the built-in After Effects Render Queue
5. Edit > Purge > All Memory & Disk Cache
6. Manually Purge Disk Cache-Preferences > Media & Disk Cache,” where its location is displayed. Open this folder and ensure its contents are deleted.
7. Run (applications- utilities- console) crash report
8. reelsmart motion blur(precomp first)
9. VC Reflect(collapsed layers) from Video Copilot
10. any scripts/missing fonts
11. The ‘Secret’ preference purge every 5 frames
12. Remove file “AVI Importer.component” in /Library/QuickTime.
12. After effects did not have permissions to a system folder
11. Download “AppCleaner” – delete quicktime

[Chris Wright]

1. Make Sure The Composite Preview During Trim is Turned Off and also make sure your Reference Monitor is Also Closed it Will Help Solve the Choppy Playback

2. change the audio hardware settings
Preferences : > Audio hardware > Default Input: to none

3. install latest updates for Adobe and your gfx card

[Chris Wright]

This may not be the error directly, but some people have had issues with realtime playback with Lumetri luts enabled, expecially 3rd party luts.

[Chris Wright]

if you have After Effects CS6, it has optical flow/timewarp
Mac has compressor, FCPX has it built in
Twixtor is available from REvision as a plugin

then of course there’s hardware devices like the Terenex 2D and Aja FS1-X
or if you like scripting, there’s ConvertFPS for avisynth.

[Chris Wright]

in this case, I would recommend optical flow if you wanted to keep a 24 timeline.

https://blogs.adobe.com/premierepro/2015/12/optical-flow-time-remapping-tips-tricks-for-best-results.html

[Chris Wright]

its probably that variable framerate stuff that adobe can’t read.
I recommend using handbrake to encode as quicktime png so you won’t lose any quality.

[Chris Wright]

yes, XAVC. haha that’s what I meant.

[Chris Wright]

imho, “at least one of the PNG frame’s highlights was clipped upon immediate import back into Premiere” = BAD Prores file.

the audio transient also gave it away.