Issues after upgrade to Joomla 4, STATE field not showing for shoppers

[lumis]

Hi, we've recently upgraded to Joomla 4 and are experiencing an issue with PayPal payments, and also with Shoppers STATE not being saved.
The PayPal issue may be caused by the STATE field issue, so I would like to tackle this first.

After our upgrade to Joomla 4, users are finding at checkout that the STATE field is blank, and they see an error message "Required field is missing" when trying to checkout regardless of what payment method is chosen.
If the user selects the STATE and then tries again, the payment is processed and the order shows their STATE.
If I look at the SHOPPER in the admin area, I can see their selected STATE.
If the shopper logs in and either goes to checkout OR manages their account, they will see the STATE field is empty.
If the shopper selects their correct STATE and tries to SAVE their account details, the user is shown the 'User data stored' but they still see an empty STATE field.
If I check in the admin area, the shoppers state IS actually updated correctly, but when the shopper views their account it once again shows the STATE as empty.

In summary: Shoppers always see an empty STATE field in checkout and account details.
When a shopper saves the STATE in checkout or account details, the admins can see their STATE, but the shopper still sees an empty STATE field.

Any ideas on what would cause this - could it be the VM template?
I'm using one of Virtueplanets templates.
Joomla 4.3.3
VirtueMart 4.0.12 10777

Thanks in advance,
Aaron