In 2020 the National Wood Flooring Association issued new guidelines for installation, and although it's a lot of the same, there's one area of the guidelines that should be paid particular attention to, Radiant Heat.
From the NWFA...
"Most wood flooring can be installed over radiant heat, providing all of the necessary conditions are met."
A link has been provided below to view the new guidelines. The radiant heat section has been expanded considerably to accommodate for the new radiant heat standard. Essentially the NWFA now outlines most major types of radiant heat in the instructions, provides guidelines for the operation each system, and then asks that the wood flooring installer pass allowable specs for the system to the engineer installing the radiant heat system.
The idea is to push the onus onto the radiant heat system. "We will install this wood floor over radiant heat providing it meets this spec."
Most major brands peg their installation instructions to the NWFA standard for installation, so expect some updated installation instructions from major hardwood manufacturers down the line.
Each manufacturer has their own installation instructions, and those instructions must be followed in order to maintain a warranty, so don't change anything until you hear from a vendor on the matter.
If a manufacturer indicates that a product can't be installed over radiant heat to maintain a warranty, then don't put it over radiant heat, but it is expected that some changes will be coming based in the new NWFA guidelines.
The long and the short of it is that if a customer wants to have wood put over radiant heat, then they had better have all of the specs on the radiant heat system handy before an installation can be committed to.