Quantum Break's removal from Game Pass is down to licensing issues, Microsoft has confirmed...
Microsoft working to renew Quantum Break licenses, Microsoft said Quantum Break's removal is due to"current licensing issues." Microsoft also said that the team is working to get Quantum Break back on Xbox Game Pass as soon as possible, but XDynasty reports that no agreements over licenses have been reached thus far.
Quantum Break launched on April 5th, 2016, so it's possible we could see the game drop out of Game Pass and even be delisted shortly. Interestingly, Quantum Break has been discounted by 80% in the latest Xbox sale, and this discount ends in two days. Here's hoping Microsoft can sort out whatever licensing issues there are, and all this is just temporary.