I dunno, I'm not reading anything into that Elon tweet about issues. He says so much cryptic, random stuff, and most of it usually ends up meaning something completely different than what most folks would infer. There may be nothing at all wrong with the car, and he could be talking about transportation, distribution, or delivery issues.
Based on all the evidence, my guess is that the cars are fully baked and ready to go, just waiting on final word from NHTSA on whether they can ship with a yoke. So Tesla starts the line and working process improvements to increase output in the meantime with a backup plan to retrofit depending on NHTSA's final call. It's why we're not seeing them churned out by the hundreds yet: they don't want to throw away TOO much money on yokes they have to trash, yet they want to be prepared with cars sitting in dealer lots with contingency wheels to hit the ground running when NHTSA gives the word. Theoretically this would let them have at least some cars delivered by EOQ. This scenario lines up both with Elon's cryptic tweet about issues and the NHTSA recent statement. It also fits with the original expected timeline of shipping in late Feb/March; Tesla probably got estimated approval timelines and (reasonably) based their delivery announcements on them. This is all well and good, but federal bureaucracies do NOT march to the beat of anyone's drum, and I can tell you from experience that these kinds of regulatory bodies are almost always untimely and disorganized.
