giomode Thanks for sending the skeleton data files and the Spine project files. I have seen the Spine project and I have confirmed that I can play the animation with the exported data, but I don't know the difference between your expected result and the result at runtime. Could you send us some screenshots showing the difference between the expected results and the result at runtime?
By the way, you mentioned that your project uses Pixi.js, but unfortunately when Spine 3.8.99 was released, there was no official Spine runtime for Pixi.js and only third-party runtimes were available, so if the problem you are experiencing is caused by the third-party runtime, please note that we are unable to provide support.