IANAL, and might be (likely) totally wrong. Here's my take on GP's comment.
Apache v2 has an patent clause which explicitly waives the rights of the licensor over the patents they might have on the licensed code. So, presumably, it doesn't matter if the current project has a patent because it was once licensed under Apache v2, and the so those patents can't really be exercised. Unless, any new additions since changing the license are patented. Since you can say the only code you've used with the current license is the diff from since it was Apache licensed.
But all of this is moot since you can't even take the risk of getting sued over a case which cannot be thrown out, because you might be bankrupt by the time the case is over.
Also the current discussion isn't just about the current codebase. It is about using any of FB's projects using this license and problems over suing FB (and its affiliates) for any patent infringement. (Oculus comes to mind because it presumably has tons of important patents)
Apache v2 has an patent clause which explicitly waives the rights of the licensor over the patents they might have on the licensed code. So, presumably, it doesn't matter if the current project has a patent because it was once licensed under Apache v2, and the so those patents can't really be exercised. Unless, any new additions since changing the license are patented. Since you can say the only code you've used with the current license is the diff from since it was Apache licensed.
But all of this is moot since you can't even take the risk of getting sued over a case which cannot be thrown out, because you might be bankrupt by the time the case is over.
Also the current discussion isn't just about the current codebase. It is about using any of FB's projects using this license and problems over suing FB (and its affiliates) for any patent infringement. (Oculus comes to mind because it presumably has tons of important patents)