It definitely carries penalties for the attorney. Each US state has passed 'rules of professional conduct' that govern rules that apply to barred attorneys. Lying to a tribunal, or lying to your client, is illegal and you can be disbarred and fined for it.
Haven't read this case closely but it sounds to me like the attorneys said "it's possible these are deep fakes" and not "these are deepfakes." The former seems like a reasonable argument to make, but according to the judge, a flawed one.