It showed the frame rate correctly when first installed. Then after restarting my PC it now shows N/A
This was also the case with 23.40.19 and 24.1.1
The only time when it worked consistently were the beta drivers for AFMF 23.30.13.05
Edit: I'm using the 7900XTX and 7800X3D
Prior to installing 24.2.1 I also disabled automatic driver updates from Windows 11 updates just in case it might have interfered in some way.