Tracker "Track Forward" not doing anything and DVR hangs

I have a clip that I had a tracker on, which initially worked perfectly. Then I've decided to change the speed of the clip (it's a timelapse). Since the tracking got messed up, I removed the tracker in Fusion completely, and created a new one just like I always do. In this new fresh tracker, I set my tracking point, then I hit Track Forward in the beginning of the clip as normally.

Tracking should start, yet NOTHING is happening. It hangs on that frame. The UI isn't technically unresponsive but trying to anything results in the attached warning box. Hitting Yes or No doesn't matter, Resolve still is not doing anything and doesn't consume any CPU (when it does actual tracking, it consumes 900% CPU). Waiting also doesn't help.

What happened to my clip where I had perfect tracking? All I did was change the speed (from 1500% down to 800%) and re-track EXACTLY the same way by deleting the tracker and adding a new one. Restarted Resolve countless of times, and I'm about to go crazy.

Try creating a Render in Place of the clip with the Speed Change. Gives Fusion something solid to work on.

Try creating a Render in Place of the clip with the Speed Change. Gives Fusion something solid to work on.

Thank you Jim, that worked perfectly!

However, for future understanding, I'd love to know why it happens in the first place? e.g. is it a known bug that happens with Fusion/tracker/keyframes etc. on speed change? Just wanting to know it so I can avoid it.

You are generating synthetic frames with a speed change, a pretty demanding process. Together with tracking, which is also not a trivial task, your system may be challenged too hard. A RiP is separating the tasks.

You are generating synthetic frames with a speed change, a pretty demanding process. Together with tracking, which is also not a trivial task, your system may be challenged too hard. A RiP is separating the tasks.

If problem were that retime is so challenging, it would hang on the first frame of retimed clip playback. It doesn’t, as far as I read here. Tracking isn’t a freeze-worthy bottleneck with any stretch of imagination. Imho it is a misbehavior or direct bug, it has been reported in different variants for long time.

A crash should not happen at all. Any crash not related to defective hardware is a bug, IMHO. This one might be pointing to a memory issue.
The suggestion was only a workaround.

I've had some issues with Fusion rendering when I lengthened a Fusion clip on the Edit page and forgot to adjust the "Global In/Out" parameter in a Fusion media node's Inspector panel. When Fusion gets to frames beyond the Global "out" value, there's no input for it from that node and that seems to cause some problems.