When Adam Selipsky left Amazon Web Services in 2016 to become CEO of Tableau Software, he brought with him a handful of Amazon management traditions. For example, he discouraged Tableau colleagues from doing PowerPoint presentations, instead asking them to write multipage narrative documents about new projects, a hallmark of Amazon management.

Now that Selipsky is back at AWS as its CEO though, he may find himself trying to stamp up some of the traditions that have begun to seep into the cloud giant from other companies. In the years since he left AWS, it has become increasingly bureaucratic, according to four people who have worked at AWS. That is partly because AWS has expanded by hiring thousands of new employees in recent years, including seasoned sales executives from companies like Microsoft, Oracle, SAP and Hewlett Packard Enterprise, to attract more Fortune 500 customers.

The new arrivals have brought their own customs to AWS, including more paperwork and stricter management styles than AWS sales teams were accustomed to, the former AWS employees said. The changes have led to internal concerns about red tape and, in some cases, departures of senior people.