sometimes the exported json having missing frames.
not the whole character but some if its parts are missing and sometimes it shows off switched mesh.
it is good in the spine file but the exported json always keep the bug.
today i found a similar one, in the editor some of the parts of my character were missing.
i had to switch them on again and re-copy paste their last frame for each of them, since switching them on again disconnects the animation. i tried to restart spine and even the pc but the bug stayed.