I noticed the same issue on a Pixel 8 Pro and 9 Pro XL after updating to 2026030100.
It looks like now it only shows up after enabling notifications on the lock screen. I'm not sure if this is intended or not. Before the update, it would show it even if the notifications were disabled.
What's odd is if you enable and disable the lock screen notifications the alarm time would show up until the next restart.
The same is happening on the current 2026030701.