The same thing happened with the 2080 / Titan and looks to be confirmed for the 3000 series by AnandTech. https://twitter.com/RyanSmithAT/status/1301996479448457216

The Reddit AMA implies the Ampere architecture supports this configuration but is software limited under the FP32 section: https://www.reddit.com/r/nvidia/comments/ilhao8/nvidia_rtx_3...

To epistemologically correct, I don't believe one will ever see a statement from NVIDIA confirming that this is a software limitation. I believe it's just inferred.

edit: This is close to confirmation: https://imgur.com/a/RH8vyz9 -though I may suspect there are non reversible hardware fuses at play too.