I have to ask: After you've selected the content to redact, did you then apply the redactions?
I've not heard of this happening before.
I do apply the redaction as follows. I post to the web all the time, but have been informed we are no longer able to use the software because of this.
This is definately worth looking into more to determine exactly what's going on. It will require a detailed examination of the redacted documents to see if they really are retaining the information that you intended to redact. I can imagine some scenarios where what you're experiencing isn't related to a problem with Acrobat, but if it is a bug, Adobe would be very interested in knowing about it.
As a test, what happens if you use Acrobat to search the documents that you download from the site for text that you intended to redact?