I wouldn't do anything. Issuing a new number apparently triggered an off-cycle reporting, but there's nothing about that that isn't legitimate. So there's nothing to dispute or ask them to undo.
Your drop in score is temporary, and shouldn't last longer than one billing cycle. So unless you're planning on applying for a mortgage RIGHT NOW, I don't think you have anything to worry about.
I don't know for sure, but I doubt that this will be your new reporting date; I think it was just a one-off event triggered by getting a new number. You can always change your due date if you need to and that will, in turn, also change the reporting date.
Cap1 doesnt change their statement dates. I lost my Savor and they did the same as you but the statement date didnt change at all. So your next normal date will report as usual and you'll be right back where you were before. You can get Discover Scorecard to check on EX FICO 8 after your next real statement date and before your next MyFICO pull to see where you landed.
Cap One did this once when I took my Union Plus MC card out of the sock drawer and used it maybe a week before the usual statement date. They reported essentially when the charge posted. My Savor reports on the 8th like clockwork, but it gets regular use.
This was the only time I've ever had off schedule reporting from Cap One.
@ahumanontheinternets wrote:I use one of my Capitol One rewards credit cards for monthly expenses and then pay it almost completely off each month before it reports to the bureaus. I'm hoping to buy a house soon, and this keeps my utilization rate low and also seems to help with my mortgage FICO, which I've been trying to raise a little.
I realized earlier this week that there were a few transactions on the card that I didn't make. So I called Capitol One, they agreed the charges looked fraudulent, and they credited my account and sent a new card with new numbers. All per usual.
But here's the bad part: For whatever reason, they reported to the bureaus TODAY - in the middle of the cycle, when my balance is super high, instead of after my monthly payment like the usually do. The result, of course, is that my score dropped. I've already used my monthly update on MyFico, so I haven't checked to see how it affected my mortgage scores, because I don't want to pay for a new report. But I can only assume my mortgage score has probably dropped a little, and that sucks because I've been on the cusp going back and forth between "average" and "good."
Is there anything I can do? Can I call Capitol One and ask them to rescind the update? I'm guessing no but thought I'd ask.
And should I call them anyway, to make sure that today's date isn't going to be the new date that they report each month going forward?
Thanks for any help!
I believe when this happens, your account is "closed" until they can load the data from the old acct into(onto?) the new; that's why they report. When this happened with BOA, the process was flawless, and since the card had a low balance, I paid little or no attention. When my Synch PayPal was hacked, it was a PITA. We had the closure, and then for two **bleep** months I had the old card reported as closed with a new account appearing as brand new. So a) I take a decent hit for 31% usage on that card, b) another hit for new account, and finally c) a few points for lower AoAA........I guess Synch forgot to do the hard inquiry(#SarcasmFont). If you're with one of the major players, @SoCalGardener's scenario will play out. It took two additional reporting cycles before Synch had me back to normal. To my surprise, Synch did agree to report off-cycle in MY benefit when all was complete. @FireMedic1 gave you a solid on getting your F-8 asap, but you can also sign up for EX's free service, which also gets you a freebie. The added bonus is that instead of getting junk snail-mail and email from Discover, you'll be getting it from multiple cards. 
Good luck w/the mortgage