Apple recently rolled out the macOS Ventura 13.4 update to eligible devices, fixing several issues of the previous software version. Some of the problems fixed, as per the change log, are bugs in the Apple News app, a slow connection of Bluetooth keyboards, a bug in Screen Time settings, and more. You can check the change log here for a detailed list of resolved issues.
However, despite fixing many issues, macOS Ventura 13.4 still fails to fix the bug where screen savers do not work correctly for people who have setups with multiple displays.
Based on several reports by people on GitHub, if you have several monitors connected to your Mac, third-party screen savers like Aerial will not work appropriately. The issue is less severe for people with only two displays, though, where the content of the first screen appears on the second, and the first one stays blank. It is also less frequent on two-monitor setups. This bug likely showed up with macOS Ventura 13.3. However, it looks like it has been fixed for first-party screen savers. Speaking of setups with three or more monitors, the screen saver shows up only on one of them if it is from a third party. Some even went as far as to say that none of the monitors displayed the screen saver.
That is not the only issue, though. Some people on GitHub also report that videos are sometimes misaligned across the monitors. On Apple Community Support, reports state that the wallpapers are broken and do not change at the selected time intervals.
Currently, there does not seem to be any working fix for the screen saver bug. All you can do is use the first-party screen savers provided by Apple to get around the issue. People have contacted Apple regarding the same, but Apple has not acknowledged it yet. Apparently, people using the beta firmware of macOS Ventura 13.5 have claimed that the issue is still present, even for two monitor setups. Speaking of the wallpaper bug, that also has only a workaround. You need to log out and then log in again to get rid of it temporarily. We hope Apple resolves these issues quickly with the next update to give users a hassle-free software experience.