"Since they are distinguished only by the time delay, revenue...

"Since they are distinguished only by the time delay, revenue and cash receipts should indicate the same trend for sales growth."
In an ethical and properly conducted business that is the case. However we have seen instances of revenues being overstated through devious means but you can't fudge the cash figures.
As Taurean suggests receivables would be where you would look for an explanation of any major variation.