Hi Julen,
Fully agree with your observations. The behavior by which HP software resets the monitor into racing mode also reappeared on my system. In my memories 2 - 3 weeks back. As from other posts not via an HP software update by Optional Updates in Microsoft Update. No this time the hard way.
I got enjoyed as well and took the hard way to solve it. I followed the comments of another user in this who said 'uninstall HP One Agent' (not jus disable it) which indeed made the racing mode issue to disappear (again).