I'm not sure if this is a bug or just the way it works.
The solution is to nest the clip and adjust it's time there, then apply the motion effect to the nest.
I'd believe this is a bug, because of following two arguments:
- Imagine a requirement to nest each clip instance first before being able to apply any effect to it.
- The Time Remapping effect is the only effect that cannot be edited in the Effect Controls section.
I believe that, because the Time Remapping effect does not behave like any other effect, this effect must be a lost and forgotten artefact of some ancient time when Premiere Pro was version 1 or 2.
I believe the Time Remapping effect needs a redo so it will fit in again and doesn't confuse users or require special attention.
thanks for your hint. I had been trying to set the numerical value in the Effect Controls window, which is not possible. - I know, this behaviour is mentioned in the help file. But there's no reason for not having it editable.
If it was editable, the Speed context menu for clip instances was redundant. It's currently rather confusing and inexplicable indeed, that there are two distinct options servicing the same purpose: They are both changing playback speed.
I don't understand the statement your first part. You are giving the Time Remapping effect as the sole example to create a general guideline. Is there any second effect in Premiere Pro to strengthen your statement?