To rectify the error message:
Patch the missing UUID into the transaction (UUID already available in MyInvois Portal).
In actions (3-dots button), you can select Regenerate PDF instead of viewing the transaction.
Suggested to create a manual CN in MyInvois portal against the bill and consolidate the Bill in UBS that failed to transmit for past month.
Please raise a new case online in case you need assistance with patching the UUID.