Timeline keyframes

Has anyone else noticed an issue with the latest PS (24.6.0) when using the timeline transformation on a smart object layer: transforming between three keyframes the 1st and 3rd unchanged, with the 2nd (middle) keyframe transformed.

What I see is the animation does not smoothly change, as it always has, but simply jumps when getting to the middle key frame, ie no change - jump - back to no change.

Before anyone asks my PC has loads of ram, a fast GPU and I've never seen this issue before.