I've seen that wait type be a problem with concurrent queries that use HASHBYTES. Some details here: https://orderbyselectnull.com/2018/05/31/hashbytes-scalability/

Otherwise, I haven't been able to attribute it to a...

Trace flag 692 is documented here: https://docs.microsoft.com/en-us/sql/t-sql/database-console-commands/dbcc-traceon-trace-flags-transact-sql
Trace flag 9448 disables the referential integrity operator and is mentioned here: https://orderbyselectnull.com/2017/12/05/the-referential-integrity-operator/

The randomness component of this question makes it tricky. We don't know the full details of the columnstore compression algorithm, so it's difficult, it not impossible, to construct a data...