Sorry if I was premature. It is actually the Bluetooth driver that appears to have been updated according to the Intel Driver and Support Assistant page. I've included a screenshot from my system.
Maybe the latest driver didn't fix this issue after all. I use Nord VPN and that software was also updated a couple of days ago.
Anyway, something has very recently got my icon working correctly. I noticed the correct icon as soon as I updated the Intel driver, so I'm still happy, but perhaps I am wrong about the reason? If somebody works out exactly why the icon has changed, please let us all know...
Z690 Hero, 12900K, BIOS 4001, MEI 2433.6.3.0, ME Firmware 16.1.35.2557, 7000X Case, RM1000x PSU, ASUS TUF OC 3090TI, 2 x 16GB Corsair RAM @ 5200MHz, Windows 11 Pro 23H2, Corsair H150i Elite AIO, 4x Corsair RGB fans, 3x M.2 NVME drives, 2x SATA SSDs, 2x SATA HDs.