Serilog.Expressions how to use the wildcard indexing (any) operator on a dictionary

I'm using Serilog.Expressions (3.4.0) to try to filter SQL injection attacks appearing in the query string. I've enriched the log event with the query string as a dictionary. It appears in my output as:

QueryString: {
    someKey: "UNION ALL SELECT NULL,NULL,NULL,NULL,NULL,NULL,NULL#"
}

I can successfully filter by specifying the key:

QueryString['someKey'] like '%UNION ALL SELECT%' ci

However, if I change the index to the "any" wildcard, the expression no longer matches the log event:

QueryString[?] like '%UNION ALL SELECT%' ci

Am I doing something wrong, or is this not supported?