What is System Data on my iPhone 13 Pro Max?

I would ignore that because this system data will make room when you need more space on your iPhone.

On an iPhone, the term "Other System data" refers to a category of storage that includes various types of system-related files and data that don't fit into specific categories like apps, media, or documents. Some of It represents data that is necessary for the functioning of the device but doesn't fall into easily identifiable categories.

"Other System data" can include things such as system files, cache files, logs, system updates, diagnostic data, temporary files, and more. It's a catch-all category that encompasses a wide range of data used by the operating system and built-in apps.

Sometimes, the "Other System data" category can take up a significant amount of storage space on your iPhone, and it's not clear to me what specific files or data it comprises. If you notice that your iPhone's storage is almost full and the "Other System data" is occupying a large portion of it then...

• Restart the device. That's it.

If the above does not resolve the issue then...

You may --> Clear Other storage on your iPhone or iPad - Apple Support (IN)

Tap on System Data it will take you to "Other System Data"

Now the question is what is the "Other System Data" storage. Read on...

• Other System Data: Non-removable mobile assets, like Siri voices, fonts, dictionaries, non-removable logs and caches, Spotlight index, and system data, such as Keychain and CloudKit Database. Cached files can't be deleted by the system.
• System: Space taken by the operating system. This can vary based on your device and model.

About cached files in "Other System Data"

Finder and iTunes categorize cached music, videos, and photos as Other instead of actual songs, videos, or photos. Cached files are created when you stream or view content like music, videos, and photos. When you stream music or video, that content is stored as cached files on your device so you can quickly access it again.

Your device automatically removes cached files and temporary files when your device needs more space.

If storage on your device differs from what you see in Finder or iTunes

Since Finder and iTunes categorize cached files as Other, reported usage for Music or Videos might differ. To view usage on your device, go to Settings > General > [Device] Storage.

If you want to delete the cached files from your device

Your device automatically deletes cached files and temporary files when it needs more space. You don't need to delete them yourself.

It surely is not iOS 17.4.1 because...

I conducted a thorough search of this forum and uncovered numerous posts detailing similar issues across various iOS updates. This suggests that iOS updates may not consistently be the root cause. Below are a handful of examples extracted from the search results:

"After iOS 17.4.1" will be an addition to this list posted by you.

• Clear Other System Data on iOS 15.5 (19F77) for iPhone and preventing it to swell again....
• After updating to IOS 15.4, I've noticed the system data is taking a lot of space. I had 90 gb free space before updating and now it's shows around 82 gb. What can be the 
• I am using Iphone Xs 64 gb and other system data take 9gb of space and iOSversions 16.0.3...
• After my IOS 15.7 update. My storage was 69GB, then I noticed it jumped to 93GB. My system data is taking 49.59GB. Is there is resolution or what?...
• On iOS 17.1.2 I have 257 GB memory, out of which 176GB is system data. Everything I clean from apps goes directly to system data. Restarted the phone many times. Any help? iphone 15 Pro Max 256 GB MU793ZD/A iOS 17.1.2 21B101...
• My system data and other system data were 5.1 Gb and 5.6 Gb on my old iPhone SE 64 Gb. (SW version 13.5.1) Today, on setting up my new iPhone 13 (256 Gb), SW version 15.5, I now have 9.1 Gb iOS and 44.0 Gb Other System Data! This is surely insane! What is happening here??...

It's not always the iOS update's fault!  Many things can cause phone problems.  If you tell people you think it's an iOS update, it might make it harder to fix or find a solution for the real issue.

Remember, the right question often leads to the solution!

iOS updates aim to enhance user experience, boost security, and fix bugs rather than disrupt core features. The majority of the issues after updates might stem from underlying, unmentioned factors. Updates won't typically alter personal data but may refine settings or features. Backup before major updates for safety. Review Apple's update details and backup advice for a smooth process.

Kindly consider checking your settings and addressing any device issues before attributing the issue to external factors. This could be a pure coincidence that the iOS update affected the iPhone functions.

Before initiating a standard iOS update, it's advisable to create a backup. Have you completed this step? If yes, proceed with the restoration from the backup.

See what each update does: About iOS 17 Updates, About iOS 16 Updates, About iOS 15 Updates, About iOS 14 Updates, About iOS 13 Updates, About iOS 12 Updates, and so on...