It's not true.
I don’t know if the rules that my system put in place at the beginning of the pandemic are still in force. They may have put that rule in place just to make sure we all went online when this mess first started. I just know I’m not going back to the classroom until most of my colleagues do too. My college is still almost entirely online.
EDIT: Chancellor’s memorandum was about cleaning protocols. The union advised us on liability issues and said that we could be liable for sicknesses if we fail to follow the protocol. My union membership includes a $1 million liability coverage for the classroom. They might have brought up this as a way of saying that our classroom insurance does not cover this possibility.
https://www.insidehighered.com/news/2020/08/03/students-aske...