my iphone 12 doesn;t sync gmail with my ipad since 16.3.1 install

Hey there dc_Gnome,

We'd like to help by first better understanding what's happening, along with ruling out some possible causes:

1. You mentioned this began after updating your iPhone to iOS 16.3.1, but have you already tried a restart since doing this? Sometimes unexpected behavior can be resolved with a restart: Restart your iPhone and Restart your iPad
2. If you're using a compatible iPad model, the latest would be iPadOS 16.3.1. You can verify this within Settings > General > About. In case you needed it, this link shows how to first back up, then Update your iPhone or iPad.
3. If you test reading a new email first from your iPhone, does it show as 'read' on your iPad?
4. Have you noticed email from other accounts acting in the same way when first read on your iPad besides Gmail?

Cheers!

Salutations Dave, 

Let’s test something, when you read or delete an email on your iPad, then sign in on Gmail’s webmail does that change reflect there? That’s going to tell us whether the issue is the push from your iPad to Gmail or Gmail to your iPhone. 

Next, can you also test whether you’re able to send and receive email on your iPad? You can attempt to send an email from yourself, to yourself. That will test both. 

If the changes on your iPad do not reflect via webmail, then what we’d like to have you do next is go to Settings > Mail > Accounts to remove and re-add your account on your iPad. 

1. Tap the email account that you want to remove.
2. Tap Delete Account.

To add your account again, this article will walk you through it Add an email account to your iPhone, iPad, or iPod touch

How to set up your email account automatically

If you use an email provider like iCloud, Google, or Yahoo, Mail can automatically set up your email account with just your email address and password. Here's how:

1. Go to Settings > Mail, then tap Accounts

2. Tap Add Account, then select your email provider.

3. Enter your email address and password.

4. If you see Next, tap Next and wait for Mail to verify your account.

5. If you see Save, tap Save.

Thanks. 

Hi dc_Gnome,

You are most welcome.

Cheers.