For what it's worth, the CNCF is not big on CLAs in general although, as far as I know, they don't specifically prohibit them. In general, they prefer to use a developer certificate of origin.
According to the link below:
> Anyone who is contributing any code to any CNCF project must have the CLA signed.
https://contribute.cncf.io/resources/glossary/#:~:text=Contr...
It’s [a Developer Certificate of Origin] how the Linux kernel works, where basically it takes all the basic things that most CLAs do, which would be like, ‘Did I write this code? Did I not copy it elsewhere? Do I have the rights to give this to you, and you sign off on?’ It’s been a very successful model played out in the kernel and many other ecosystems. I’m generally not really supportive of having CLAs unless there’s a real strict business need."
https://opensource.com/article/20/2/open-source-projects-gov...