I encountered an error a while ago in my reboot shuttlecraft where it slowely rolled to the side in normal flight. I managed to fix that by rearranging the nacelles. Later, while making my klingon bird of prey, i encountered the same problem, but fixed it by turning the outer part of the aircraft's wing into a structural panel, rather than an actual wing. Does anyone know why this is happening?

Please let me know, here is a link to an aircraft with that problem.
https://www.simpleplanes.com/a/jl2Au3/Reboot-Shuttlecraft

Thanks.