Send for Signature sends, but signatures don't show up

Hello,

I just discovered the Send for Signature tool in Adobe Acrobat Pro DC, and set it up with fillable signature fields, including the emails of each of the signers, 1 through 4. Then sent it out - it is automatically going through the emails as the people are signing it, but after 3 people have signed it, only one of the signatures actually shows up. I can click on the place where the other two signatures should be, and it tells me that the transaction number is valid, but there is nothing actually visible in that field.

Has anyone had this issue, and do you know how to fix it?

thanks,

Heather