@Bevan Thomas, Thanks for posting in Q&A. From the error message, it is failed to get enrolled User SID on the affected device when deploying MSI LOB app. Please go to the affected device and sign in with the enrolled user then sync on the device side to see if we can get the MSI download.
Meanwhile, you can follow the steps in the following link to troubleshoot to see if there's any more finding.
If there's any update, feel free to let us know.
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