Sql-runner hit - ERROR #XX000 basic_string::_M_construct null not valid when attempting to run REFRESH MATERIALIZED VIEW.
The view in question was constructed with LEFT joins, which it seems may not be supported as per the docs, however the nature of the error itself suggests that something isn't being handled correctly. Also the customer had been successfully running the same query on the same view for a long time before hitting this error.
May be a driver issue, or some other poorly handled error. Attempt to reproduce the issue, investigate what Redshift throws back, and investigate how that's handled.
Also investigate if simple driver update resolves.
ZD ticket #28488