One of my signers is getting "You are next to Sign, but the envelope is still processing. (will automatically try again in 10 seconds) TRY AGAIN" Has anyone else seen this before?

Sometimes this can happen if the signer is eligible to sign at the time the signer opens the envelope, but then something in the envelope changes to make the signer ineligible. For example, if a sender corrects the envelope and adjusts a signer's routing order to a future routing order, the signer might see this message until the routing order advances. In your NDSE member console, you could go to the Document Details Page for this envelope and see if the signer still appears at the current routing order.