Multivariate Normal Imputation Error


I am currently working through converting the code in the pymc-resources/Rethinking_2 directory to pymc v4. I have forked the repo and have been working on updating the code as I read the book. In code block 15.22 I get this error message:

Here are the package versions I am running:

It appears that this was a possibility on pymc3 according to the issue/discussion on this discourse link. Is there a different way that imputing multivariate normal random variables should be handled in v4?