[just another ref]

Originally Posted by Camron Rust

2.3 is not an option when we've got cases that already cover when it is too late to correct an incorrectly called infraction.

Is there a case which deals with anything close to this?

Official calls improper technical due to erroneous information from the scorer.

As you say, everything cannot be covered in the books. Sometimes you just have to do something because it makes sense.
I would probably rescind the T at any time this information was brought to my attention. The free throws are covered by rule.