This could be a bug - peculiar transformation behaviour

I’ve noticed a weird thing tweaking an animation at the moment. I’m animating a simple object, no armature, just keyframing it’s locrot.

Trying to adjust a keyframe in the 3d view. If I g-key translate it, and then rotate with the manipulator all works as expected.

But if I do the reverse, rotate (with r or manipulator) then g translate it, the object snaps back to its original position and rotation. Ouch! I don’t think I’ve come across this before. It can be worked around by I-keying after translating but that’s really annoying - as I normally need to tweak location and rotation a number of times in succession before locking in the keyframe. If I do a succession of grabs and rotates sometimes after a grab, just the rotations that I’ve done are reset/lost.

I usually assume I’m doing something wrong. I thought this might have just come up in recent builds but I just tested the blend back through to 2.59 with the same or similar results… ?

I’m on Mac PPC 10.5