Do not worry about it.
The IRS changed their reporting requirements effective Q2 2015. One of the requirements included a “Name Control” field which is essentially the first 4 characters of the company name. This is now showing up in the IRS records in the “c/o” (care of) line causing the notices to be issued.
If you received a letter from the IRS stating they received an address change, you do not need to take any action.