“Employee engagement” has become a mantra in Corporate America, for the most part signaling a healthy desire for their employees to feel fulfilled in their work—and thus productive too.

But is there a point where this virtue becomes a vice? New academic research suggests that employees who become too devoted to the job can start to exhibit negative qualities. Among them: having unrealistic expectations of their co-workers, showing a disregard for rules and regulations, and having problems in their personal lives, reports journalist Alina Dizik in the Wall Street Journal.

“Deeply engaged employees who become more difficult to manage can be overly demanding of superiors and become suspicious of their intentions, says Stuart Bunderson, professor of organizational ethics and governance at Washington University in St. Louis,” writes Dizik. “When Prof. Bunderson first started looking at how zookeepers derived meaning from their work, for example, he learned that many tend to look at their job as a calling. That, in turn, made them tougher to manage than less-engaged employees. They also expected more from those above them. The zookeepers objected to placing a carousel at the zoo, for instance, because they saw it as trivializing the zoo’s mission, until it was repositioned to promote conservation, Prof. Bunderson found.”

The issue is relevant at a time when employee burnout has been recognized as a rising problem and hustle culture, particularly among millennial workers in the tech industry, has come under attack as unsustainable. The issue: at what point does having a moral purpose on the job go too far, to the point of workers losing perspective? “There’s no such thing as acceptable compromises or good enough when things are framed in moral terms,” said Prof. Bunderson.

What can companies do to foster moderation? Some of the proposed solutions from researchers may raise eyebrows among human-resources executives.  Companies have come to believe that corporate social responsibility (CSR) and volunteerism are valuable tools for employee recruiting and retention, but some researchers on employee engagement think companies should lighten up on such programs. Instead, businesses should focus on the less-engaged employees rather than pushing programs across the board, Tomas Chamorro, chief talent scientist at staffing agency ManpowerGroup, told the Journal. “We still want them to be engaged, but moderately engaged,” he said. “A certain degree of dissatisfaction is very positive.”