I think this may be a huge problem. Here's what I found:
Can I sell my existing house owned by me or my business into my solo 401k plan?
ANSWER:
No. If you or your business sell a house/building to your solo 401k plan, it will be in violation of the prohibited transaction rule.
The same is true vice versa-meaning, neither you nor other disqualified persons may buy an existing house/building owned by your solo 401k as this would also be in violation of the solo 401k prohibited transaction rules.
By deeding the house to them personally, your client may have sold/gifted the house to themselves.
First question to ask the client is why they did this. This is very important so do not skip this. What were they trying to accomplish?
Second question: who was involved in advising the client to do this?
Last but not least, if this is a result of DIY on your client's part, let them know how much it cost them. And also let them know that your consulting fees would have cost them only x,xxx, which would have saved them xxx,xxx. And your tax consulting fees are tax deductible so their real cost is only xxx. Good luck!