so i decided to remake one of my old mods i made in automation, one i even posted on the Beamng.Drive website way back when and when i finally finished and exported it, it immediately says instability detected. i have tested this on several computers too, same issue. if necessary, i will attach a google drive link to the mod for you to test since my account is too new to simply attach it.
(EDIT) I have also tried changing the chassis type and moving fixtures and changing those as well and i still have the same result.