The help desk person I spoke to a few months ago when they gave me 5 days to respond gave me this information. The CRA has to comply with the 30 day timeline. Sometimes, depending on load/ other research requests, the request can be held prior to being sent to E-Oscar. Also, they may need additional time prior to your response to correspond with the customer - so they don't always give you as the bank, long periods of time. BTW: I argued with the rep about the 5 business day claim and their delete response as bogus, and we got it re-inserted.
Perhaps the initial report date is like when a customer initially disputes with us, but it isn't completely clear as to what is being disputed? I've never seen an example of this, so it's only a guess.