Thanks for sending us the project.
I've checked it with the latest spine-unity for Spine 3.6 and 3.7.
It doesn't seem to be showing the problem you showed either in play mode or in the inspector preview.
If you haven't updated your Spine-Unity in a while, maybe updating to the latest runtime will help fix it on your end. Spine Unity Download
Otherwise, is there anything else in your setup you can describe to help us replicate the problem?
Just an additional tip:
Your skeleton has a lot of smoke images hidden via alpha. If you set your slot color alpha to 0, it will still be rendered by the game engine and GPU and eat away at your fillrate budget. It will be more performant if you key hiding those attachments using the visibility dot in the tree.