KPerev Thank you for sending us your Spine project files. This is certainly not a Unity implementation issue, but an animation configuration issue, as it can be reproduced in the Preview view of the Spine editor.
The animation that is causing the problem is changing the position of the head and face parts with the animation set to track 1 before the switches, but after the switches, the animation set to track 0 changes the position of the head and face parts. Then, when the animation that was playing on track 1 mixes out, the position of the face parts does not stay in the correct position, and you can see them trying to move back to their setup pose.
To make this problem easier to understand, I have recorded a video and emailed it to you so you can check the contents.
If multiple animations are being played simultaneously to achieve a particular pose, you should try to play the animations that animate specific bones on the same track as much as possible.
