Hello hkbs,
Thank you for reaching out in Apple Support Communities. Are you noticing this behavior with your iCloud account or a third party email account?
In addition, let's ensure that your iPhone is updated to the latest version of iOS 16.3.1. This helps provide software improvements that may help. If needed, here's how:
"Update your iPhone or iPad wirelessly
- Back up your device using iCloud or your computer.
- Plug your device into power and connect to the internet with Wi-Fi.
- Go to Settings > General, then tap Software Update.
- If you see more than one software update option available, choose the one that you want to install.
5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do."
These steps are outlined here and it may help: Update your iPhone or iPad - Apple Support
Kind regards.