@Midonk Sorry to hear you're facing problems again! Unfortunately we could not reproduce this issue though, when changing the clip's Speed Multiplier to 2 the animation played back twice as fast during play mode, and half as fast when using 0.5.

Could you please share reproduction steps or a minimal Unity project with us that still shows this issue? You can send us a zip package to contact@esotericsoftware.com, briefly mentioning this forum thread URL so that we know the context. Then we can have a look at what's going wrong.

Midonk My bad for this one, false alert. I have been mislead by the sounds of the timeline.

Ok, thanks for the info, glad to hear.

Midonk By the way, the preview plays at timescale = 2 * SpeedMultiplier, I already tested it on a new project. But this belongs to another thread I suppose

Thanks for reporting! It turned out that Unity fixed a bug regarding the returned clip speed not being included in clip time some time ago (Unity 2018.3 still has this issue, 2019.4 not). This made an old workaround added by us wrong and obsolete.

We have just fixed this issue. A new 4.1 Spine Timeline UPM package is available for download:
https://esotericsoftware.com/spine-unity-download

Issue ticket URL for later reference:
EsotericSoftware/spine-runtimes2312