Character animations accumulate rotation (update: curve missing)

I am observing what seems to be an accumulation of rotation in one of the animation nodes of an animated character. After playing several animations on the same character the end result is that one of the animations nodes is rotated. For example from an idle to run and back to the same idle, the character has a pronounced hunch. I don’t see that I’ve switched on layered or additive animations anywhere.

UPDATE: I now notice it appears to be one node only within the character hierarchy, it retains the rotation from the last animation at whichever point the animation was removed for the next. Still working on refining what is happening.

If one animation concludes with a node in a given rotation and the subsequent animation has no curve for that node’s rotation property, the old value will persist. Check what curves exist for that node by inspecting it in the Animation window (or in your modelling software).