Unlike previous beta programs, the final beta of the 10.3 program is not the same build that was released to the public. And for some reason, devices with the beta profile installed aren't seeing the update.
Thankfully, there's an easy way to get your device back on the right track as 9to5Mac pointed out.
- On your iOS device, open Settings > General > Profile & Device Management.
- Select the iOS Beta Software Profile, then tap Delete Profile.
- Enter your passcode when prompted.
- Finally, restart your iOS device.
When it powers back up, open Settings > General > Software Update. Your iOS device should then find the update. If not, back out of the Software Update screen and go back into it (I had to do this once in order for it to show up).
Install the update as you normally would. Keep in mind now that you've removed the beta profile from your device you will no longer receive any beta updates in the future unless you revisit the beta program website and re-download the profile.