Found in Pepper Branch, now in Trunk.
Animations in different layers shouldn't affect actions in different layer. But it happens. How to repeat it: open the file.
Action "loop": StartFrame: 0, EndFrame: 50, Layer: 0
Action "reset": StartFrame: 0, EndFrame: 5, BlendIn: 5, Layer: 0
There's a action in loop (starts with Z key). When you press X key, an Action in the same layer reset the bones loc-rot-scale.
In this way, everything it's ok. Now... let's play the bug.
Uncomment "own.playAction('layer',....)". It modify the scale or rotation of another bone in another layer (1). It shouldn't affect layer 0... but it affects it. Try it by yourself. It starts resetting, and, 5 frames later, it get back to a previous pose.
The only way to avoid this error is giving "reset" action a EndFrame and BlendIn of 10 or more (in this case). For the visual, it is not so much difference... but it shouldn't work like that.