Seller signed a new 12-month rental agreement post-offer accept

[Andrew C.]

Hello. We're supposed to close today, and I probably should have noticed this sooner (as should have my agent probably)...

I'm buying a duplex. One unit is vacant, the other is occupied at below market rent (850 vs ~1150/month...although the unit needs some rehab, so that's arguably closer to fair market given its current condition). 

Offer was accepted (e-signed, etc) on 8/7.

Buyers agent verbally indicated that the existing lease ran through March of next year.
The seller forwarded us the lease agreement on Monday - I'd been asking for it for more than a week. I just noticed that it was e-signed 8/14 (the day before he sent it) and is a 12-month least that runs Sep1 2022->Aug31 2022.

so it looks like the seller signed a new lease agreement with the existing tenants after the offer was accepted. They are not supposed to do that, correct?

They're decent tenants. They've been there 7 years. I'm not at all opposed to them staying. My plan (not yet communicated to anyone) was to rehab the lower unit and then ask them if they'd like to move down there, possibly keeping the rent the same through the end of their contract and then going to market value. I have an existing arrangement with my lender that as soon as I'm done rehabbing both units I can cash-out to 80% of the ARV by increasing the loan amount (they'll just fwd me the funds)...so I'd like to not drag this out any longer than necessary.

how would you handle this?