From GameWatcher: “For Honor is a person-versus-person hack-and-slash and, as such, it is crucial for smooth gameplay for people not to be leaving matches left and right. One of the ways in which this is incentivised is the For Honor matchmaking penalty.
What is the Quit Penalty in For Honor? – you might be asking, and the answer to that question is that it’s a simple matchmaking cooldown, though it does get a bit egregious sometimes.
Source: N4G PC For Honor Matchmaking Penalty – What is the Quit Penalty in For Honor?