Short claim procedure needed for old policies

Section 45 of Insurance Act says claims can't be rejected in policies older than three years. Then why demand so many papers in such cases?

The Covid-19 pandemic has focused the spotlight on the life insurance industry’s death claim payment process. An example will illustrate its lacunae.
 
As part of the comprehensive financial advice our firm offers, we review clients’ risk coverage and recommend appropriate insurance policies, which they buy either directly or through an agent/brokers. Claim processing, too, is handled by the clients themselves or their agents/brokers. 
 
Mahesh, a client, unfortunately, passed away recently and there was a death claim on his life policies. He had purchased three large term policies through an agent (one from LIC and two from private insurers)