Posting your result link would help us determine what you ask, but yes I have seen Futuremark's program read/report things incorrectly.
 
It has shown that my 10940X runs at 29GHz for example...
 
Edit: 31.3Ghz in this one: https://www.3dmark.com/pr/428479

And what does PX1 or afterburner or GPU Z report with a 3D load?

The detected speed on the 3DMark landing page (the page it shows when it loads) is the BASE clock.  The card will literally never actually run at that clock unless it's in low power 3D mode, that's where the clocks cap out in low power 3D mode, anything higher than that is full 3d mode, and will go from the lower boost clock (1710) up to over 2GHz.
That is completely normal & almost everyone's 3080 shows that way on that particular "page" of 3DMark's application.
 
Edit: This is what mine shows, and it's actually running at around 1995-2025 in benchmarks/games with the voltage/clock curve I have set:
 

 
So yep, that's completely normal.