Firmware and software issues can affect only certain devices at certain times. For example, the current iOS (13.4.1) has a MAJOR battery issue across most of the compatible devices (including my own) -- you can see both the iPhone and iPad forums (and other portal sites) dotted with threads about the bug. But it doesn't affect every single device.
The ANC issue is something that affects all devices as it is not a "bug" as much as it was a "change" in the firmware's coding for the ANC. We thought it was a "bug" but since it's been 6 months and Apple has been radio-silent (and entirely cut off communication with me and most of the largest thread on this forum with 653 replies, 46,130 views, and 2,429 people marking that they have the problem as well: https://discussions.apple.com/thread/250887615), I believe it was a purposeful change. For what reasons none of us know. There is no change log for any AirPods firmware which is silly and needs to change.
Also, people who bought their AirPods after early-mid November which came shipped with 2B588 (or updated automatically very quickly) have no baseline to compare the ANC performance to that was in 2B584 or 2B57X (or anything for the demo models in the Apple stores)... Thus there cannot be any "new" cases of this bug as only people who had the previous firmware would even know there is something "different" in the first place. 45,000 views shows me that most people who own APPs and are on this forum are aware of it.
But the last two iOS releases (13.4, 13.4.1) and the last 3 AirPods firmware releases (2B588, 2C54 [pulled], and 2D15) have been bug-ridden. But not all bugs will show up on every single device.