UseEnumCheckConstraints does not respect DbContext conventions

[iPilot]

When enum is derived from ulong and used as a type of a property that translates to a table column with TypeName configured using

protected override void ConfigureConventions(ModelConfigurationBuilder configurationBuilder)
{
    configurationBuilder.Properties<ulong>(p => p.HaveColumnType("bigint"));
}

(regardless ColumnAttribute presence), then enum values for constraint are generated as floating point numbers (double or decimal it is not clear).

When ColumnAttribute and its TypeName property are provided explicitly then enum values are generated correctly.