cqlsh COPY FROM of map of blobs fails with parse error "unhashable type: 'bytearray'"

Background

A user reported on community.datastax.com (question #2988) that when loading data with cqlsh using the COPY FROM command into a column with map<text, blob>, it returns a parsing error like this:

Replication steps

I can easily replicate the problem with this simple table:

I have this CSV file that contains just 1 row:

And here's the error when I try to load it:

The unhashable type: 'bytearray' error is from Python so I decided to log it as a driver issue instead of DB. I'm happy to be corrected if this is not the case and just let me know. Cheers!