This is default Spine behavior. It assumes you WANT to keep the state from the previous pose unless you key the positions and images (because of some advanced stuff you might want to do).
That it uses PlayMaker doesn't matter.
There are two ways to fix this:
One is to key all positions, rotations, scale and slots at the beginning of all your animations.
This can get old really fast, especially if you don't need the advanced stuff and have a lot of animations.
The other way is to add a handler to AnimationState's Start event in code to call SetToSetupPose on the skeleton.
If you could share what code you already have, maybe we can show you what to add and where verbatim. It's pretty much just 1 to 3 lines of code, depending on what your setup is.