From the first week when the audios where still new I have been wondering about this.
I listened to all of them and came to the conclusion that the issue is with the buffering material used with Ester C (the recommended form of C) not the C itself.
I came to this conclusion because in one audio Dr. Flechas stated that he has patients that drop it into their grapefruit juice...
One of those posts should be on the first couple of pages on this forum, I hope.