The client portfolio constructed by the adviser not falling on the efficient frontier is not a limitation but the result of classifying an investor into a behavioral type. It results in a portfolio that is better suited to the client given their behavioral biases.
Limitations of classifying investors into the various behavioral investor types include:

• Individuals may simultaneously display both emotional biases and cognitive errors all the while seeming to act rationally, making it difficult to classify the individual according to behavioral biases.
• An individual might display traits of more than one behavioral investor type, making it difficult to place the individual into a single category.
• As investors age, they will most likely go through behavioral changes, usually resulting in decreased risk tolerance along with becoming more emotional about their investing.
• Even though two individuals may fall into the same behavioral investor type, the individuals should not necessarily be treated the same due to their unique circumstances and psychological traits.
• Individuals tend to act irrationally at unpredictable times because they are subject to their own specific psychological traits and personal circumstances. In other words, people don’t all act irrationally (or rationally) at the same time.