I'm based in the UK & was told it was compatible by Intel CS along with my PC manufacturer prior to purchase.
The fact it works perfectly fine aside from picking up 5GHz makes me think, there's something that needs to be addressed.
I already mentioned that I had contacted my OEM along with Intel & was explicitly told it was compatible.
This is the only place to get support for it, seeing as official support for this Intel part is now non-existent.
That doesn't answer or address the matter I have stated. The reason behind the item not working correctly should be troubleshot on a support forum instead of passing everything on to someone else (OEM already said it was compatible).