Was the SQLServerDialect something being driven by the configuration or was that something that Hibernate was defaulting? We added a fix in HHH-11220 Closed to adjust the dialect resolution for SQLServer which is why I ask how the legacy dialect was being influenced because that was fixed in 5.2.5 (and your logs show 5.2.10).

I'll change my test environment to force the legacy dialect to reproduce. Ideally we'd prefer using the legacy dialects on newer database platforms to not be broken, e.g. they should be backward compatible but with just less features or less than optimal choices for the environment where possible.