plainklaughter Thank you for sending your Spine project! The problem seems to be caused by the following change which was made in Spine 3.7.16-beta:
Fixed path fixed position, fixed spacing, and percent spacing when the path bone is scaled.
Since the Spacing mode of the path constraint long is set to Percent, I assume it is affected by the above change. In fact, if you change the scale of huanying, which is the parent bone of the path, from 0.5 to 1.0, you can reproduce the same result as Spine 3.8 in 3.6.53.
I am afraid to say but the current behavior of Spacing should be more correct than old versions, so you need to modify your skeleton to match it. I think an easiest solution would be to set the Spacing mode of long to Fixed and set the value to 95. This will make the setup pose almost the same as the original, and animation2 and animation3 will be animated in almost the same way. Unfortunately, animation1 does not work as it is, but it can be made to work by changing the Spacing value during the animation.
