Buyer is dragging to change ownership name on HCAD

We have just sold a house back in April 2024. Until now, the buyer has not contacted HCAD or filed change name of ownership. I contacted HCAD and was told that it is buyer's responsibility to submit the ownership change request form. We have contacted the title company several times so that they could reach out to the buyer to remind them to file for name change on HCAD.

This is almost the end of the year, and the tax office will start sending out bills for property tax. So, we probably should expect that we will receive the bill of the property we just sold back in April.

I'm just wondering what can happen next since the buyer does not initiate the change of ownership name? Also, why he's doing this? What benefit he can get by doing so? I just don't understand.