In a nutshell: Many iPhone owners are reporting serious memory management issues with iOS 13. From deleting emails to closing unsaved spreadsheets, it's definitely a frustrating issue to deal with. Perhaps this makes the case for increasing the RAM in future iPhones.
There have many reports across the Internet with iPhone owners bemoaning how aggressive iOS 13 is closing apps in the background. Reddit, Twitter, and even Apple's official support forums are replete with frustrated owners complaining about the issue. MacRumors listed quite a few quotes from people on its site as well.
iOS 12 was perfect and [I] miss it for the main reason that any time I use the app switcher to go back to my previous app such as Safari or Instagram or Facebook or anything really, the app refreshes. Back in iOS 12 I could go back [to] multiple app[s] and it wouldn't refresh. It was perfect. I'm running on an iPhone 7 Plus if it makes any difference but feel it shouldn't.
I was watching a video in YouTube on my iPhone 11 Pro. I pause the video to respond to a text message. I was in iMessage for less than one minute. When I returned to YouTube it reloaded the app and I lost the video I was watching. I noticed this a lot on my iPad Pro too. Apps and Safari tabs reloading a lot more frequently than they did in iOS 12. Very annoying.
I was working on a spreadsheet in Excel and I switched to a YouTube video for like 10 mins or so and when I switched back, the app was no longer in memory. Not just that, it also flushed all Safari tabs out of memory too. None of the games are staying in memory after 20 mins.
Developers have chimed in as well with similar complaints:
I’ve noticed this since the first 13.2 betas, and Overcast users keep reporting it as well: background apps seem to be getting killed MUCH more aggressively than before.— Marco Arment (@marcoarment) October 29, 2019
(Especially on the iPhone 11 if you use the camera, presumably because it needs so much RAM for processing.) https://t.co/Qscmsj1OGY
This really affected Prompt. Extremely annoying to lose SSH connections when switch apps.— Cabel (@cabel) October 29, 2019
In yesterday’s update we rolled out a semi-cheesy but effective fix: “Connection Keeper” keeps a running GPS-based log of where you connect to servers. Side effect: connections stay alive.
This phenomenon is pretty interesting considering that while iPhones have never had much RAM, the memory management in iOS was generally good enough to keep recent apps in memory. Additionally, these issues aren't limited to older iPhones with smaller RAM. Owners of the recent iPhone 11 and 11 Pro have also reported issues.
One reason why iOS may be so aggressive with kicking out background apps may simply be battery life. Even so, people are reporting apps being closed even if they were the last used application. Users are losing whole emails because their email client was closed after simply switching to a different application like Spotify or YouTube.
Is it my imagination or is iOS 13 more aggressively managing RAM? I can’t keep YouTube suspended at all, even if it was the last used app.— Michael Kukielka (@DetroitBORG) October 22, 2019
One common thread seems to be the camera. Due to the higher levels of computational photography (particularly in the newer iPhones), the camera app seems to be a major RAM hog which subsequently causes iOS to kick out other apps. That might explain why even the iPhone 11 Pro with 4GB of RAM still aggressively kicks out background apps.
The latest version of Apple's vaunted mobile operating system received an update to iOS 13.1 just five days later after iOS 13.0 was released on September 19th. This was followed by 13.1.1 and 13.1.2. While new features such as AirPod audio sharing came with the updates, most of it served to fix bugs that were prevalent throughout the OS. Hopefully, Apple comes out with a software fix for the memory management issues.