The iOS 26 Beta version is slightly different from the general version. A version that recently exited its Alpha phase is provided for Beta testers, so issues and errors are expected. The purpose of the Beta phase is to collect user feedback to fix these errors and resolve any user interface issues before large amounts of distribution of software.
The beta version may also be incomplete and not the final product. This means that iOS 2 Beta version is more prone to errors, failures and instability.
Also: How to clear iPhone cache (and why should I do this before installing iOS 26)
Using user feedback collected in the Beta stage, most of these errors and problems are removed, thus providing software that is not prone to problems. However, they can still happen.
An example of this process is when Apple releases iOS 17 beta in 2023. Early Beta versions had the “End” button in the call moving from the center to the right, which was a big change for iPhone users. Feedback from disapproving the Beta tester has caused Apple to move the “End” button to the center of the screen, and users are used to it.