Internal team reported the below error as root cause - "The provided tag value (GT301JP – Japan) contains non-latin1 characters." in ExecutionMappingDataflowActivityExecutor and they suggested workaround as to remove the data factory tag which contains non-latin1 char, can you please try and let us know if it works. We are working internally and will update you once we get more details and permanent fix of the issue.
Thanks for your support, hope this helps!