Previous level keyframes affecting new level?

I’m using UE5 for video production only and I’m new to it.

For each shot to render I create a new Level which of course gives me a new Sequencer. However, it seems keyframes from a previous Level are affecting the current Sequencer timeline. It’s like there are ‘remnants’ left over and I don’t actually have a new, entirely clean Sequencer after all - but of course there are no ‘old’ keyframes present in timeline.

Also, lots of very weird ‘jumping around’ happens during rendering of an animated model despite the animation previewing very smoothly (a model that had previous Level keyframes applied).

I suspect I may be going down the wrong path with the keyframe theory - but a fix for this one will be monumentally appreciated.

Many thanks.