Countless infrequent crashes reported by iOS Crashlytics. Is this phenomenon well understood?

I wanted to run this by you folks and see if anybody here has had a similar experience.

We've had a few apps on the App Store available for the past several months with Crashlytics used as crash reporting service. Over those months we managed to accumulate something like 60+ different types of crashes across about 50k users.

Some of the crashes are obvious bugs that hit a good chunk of the user base and we fix them right away. Some on the other hand occurred anywhere between 1 and 5 times over the last few months across all of those users.

Obviously from a business perspective it makes no sense to fix those once-in-a-blue-moon bugs, but I'd still like to understand if there's a well known type of issues out there that affects every iOS app that one simply cannot defend against. For example, a user pressing the home button at a very inconvenient point in time, perhaps during some kind of transition. Or perhaps, the app being evicted from memory causing a crash to be reported, etc. etc.

I couldn't quite find a common thread among the crash reports, although I did find a few along the lines of:

-[UIGestureRecognizer _shouldBegin]
-[UIApplication sendAction:to:from:forEvent:]
objc_msgSend

What do you do about bugs like these? Keep an eye on them, but don't spend time chasing them down unless they become more severe?

Solution

I have the same issue in my app. Many weird crashes with obscure class/method names, where my app is nowhere to be found in the stack trace.

I emailed Crashlytics support (which is awesome by the way) and here was their response:

Also, most of these issues only have one or two crashes. When encountering issues that are affecting very few users over a few weeks or months, then I would suggest to not worry about those very much. The reason why is that there are many different memory states that can exist. There can be random RAM issues, state of memory, mem swap, and other scenarios that are out of your control.

I'm closing the issues but continuing to monitor them to make sure they really are freak occurrences.