Agree, you don't want to compromise a trial, and it may have been the CRO's call. And I am not worried, I am puzzled and disappointed. All you say may be true. There may be some other explanation, equally benign (I have stated one). What is puzzling and disappointing is the company silence on the cancellation. It's a head scratcher.
I read that post too, btw. Puzzling as well in a few ways.