The policy rationale for this was that the federal government was one of the very rare employers that provided severance payments to those people who decided to quit or to retire. A normal understanding of severance is that if you're let go, there's a severance package that you are given. In the federal public service you accumulated for every year you worked, a certain amount of days, and it added up. After 35 years you would have so many weeks of severance pay even when you were retiring. At that time, the government proposed to unions, and this was negotiated with the core public service, to discontinue the accumulation. However, everybody who had accumulated severance had options either to leave it invested in the government, so they could take it out when they retired, or they were allowed to cash out whatever weeks they had. If you had already accumulated 20 weeks of severance, that was cashed out. This was a public service-wide initiative, and it didn't particularly affect any one group more than others.
On April 19th, 2016. See this statement in context.