Thank you for your feedback, we're sorry for the inconvenience.
Could you please click SKYBOX's Global Settings(the gear icon in SKYBOX Quest app), click the BUG icon in the upper-right corner, and send us a bug report attached with logs? You just need to tick the "upload logs" box then send the feedback with the same email address.
Btw, do you play videos via SMB, DLNA or AirScreen?
After knowing what causes the stuttering issue, we'll help you solve it ASAP.