When attempting to use QR Codes to transfer unsigned bitcoin transactions, upon using Electrum to build the transaction, when clicking 'sign' I get the following message: fromhex() argument must be str, not None

I am aware Electrum uses non standard QR Codes, but I don't believe my issue lies there, because I have used both Electrum to Electrum QR as well as non-Electrum to Electrum via QR. Both methods have been able to contruct the transaction but get the same error when attempting to sign.

All else appears to work fine, and when the exact same work-flow is done via 'file' over USB rather than QR code, everything is able to be signed perfectly.


Any idea what I could be doing wrong?

Latest Electrum Version running on an offline machine (and one on an Online machine).