Don’t worry – this is not a huge problem! If you can’t un-seal one side by reheating it and peeling it up, and then redo it (which you probably can’t), then I would cut a slit in the floor fabric perpendicular to the edge, long enough so that the fold disappears. Then simply cover the slit with patches – one on the bottom of the packraft’s floor and the other on the top. Make the patches out of 250 GSM (210D) fabric. The patch on the bottom should cover the slit and also extend onto the tube fabric so that it’ll make an airtight seal. It won’t be pretty, but it’ll be on the bottom of the packraft, so no one will see it. Cheers!