RC Support classifies it as JIRA - CNV-28823 IVR does not work properly: while reading a voicemail message, attribute "from" is read as literal number rather than separate digits and that it is in a state = PKI which stands for Product Known Issue.
RC Support Response to my case - we are investigating it as a bug on our side and there is no currently available ETA when it will be resolved. We have reproduced the issue and are working on resolving it. You will not receive much in the way of correspondence while they resolve this issue, however you will be notified when the issue is fixed.
My case 10180479 remains open and has been in this state since 1/31/2020. I have received no correspondence at all on this issue and I enter a comment on my case at least once a month.
