Fortnite Meltdown Fix Breaks Things

The Epic Games Forums have an explanation for why some users are reporting problems trying to play Fortnite, blaming issues on the patches they've had to install on their servers to defend against the Meltdown vulnerability (thanks The Verge). They provide a chart showing CPU usage on their back-end more than doubling after patching. Word is: "We are working with our cloud service providers to prevent further issues and will do everything we can to mitigate and resolve any issues that arise as quickly as possible." Here's more:
We wanted to provide a bit more context for the most recent login issues and service instability. All of our cloud services are affected by updates required to mitigate the Meltdown vulnerability. We heavily rely on cloud services to run our back-end and we may experience further service issues due to ongoing updates.

Here is a link to an article which describes the issue in depth.