Suddently broken cart, no refresh and other strange behaviors

[Jokingmind]

Hello,
I've a problem with the cart of VM.
Suddently everything has stopped working correctly.
MAIN SITE:
https://shop.barbieri-italiani.it
Joomla 3.8.4 + VM 3.2.12
If I add the first product, it works fine.
As I add the second one the cart shows only the first one. If I click to choose a payment method, it refreshes the cart page and it shows the second product too.
Things are getting even more complicated if I continue to add/remove products.
This site is offline now.
TEST SITE:
https://bidev.davide-strati.it/
Here I have uploaded an old akeeba back up, more than one month ago, with joomla 3.8.2 and VM 3.2.4
That configuration hadn't shown any problem before. But now it shows the same behavior of the main site.
This site is online and you can check it.
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Things that I have done:
restore a back up of the whole site and DB with siteground tools.
activated jquery easy plugin to clean js loading
tryed with different versions of backups.
disabled the gantry template on cart.
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Anotehr little thing: if I add the date picker in the client fields it doesn't work (show only year 2021, no way to change, and throw an error in console)

Any help?
Thanx!!

[Jörgen]

Have You updated Your PHP version? Right now VM only well only up to PHP 7.0, not higher.

regards

Jörgen @ Kreativ Fotografi

[Jokingmind]

It's php 7.0.27

[Jörgen]

What else happend ? Update of Joomla, adding module, plugin ?

regards

Jörgen @ Kreativ Fotografi

[Jokingmind]

Are info:
-> the day before the problem I have added in the head of the site the zopim code for the online chat. (It's the first thing I have deleted during testing)
-> if you log in this behavior seems to disappear, must do some more test about that, but it seems that the cart is updated correctly.

[Jokingmind]

I can confirm that the problem is related only to visitors, if you login with an account, VM updates the cart in the correct way.

Chrome devtools shows this error:

Code Select Expand

[DOM] Found 2 elements with non-unique id #modlgn-passwd: (More info: https://goo.gl/9p2vKq) <input id=​"modlgn-passwd" type=​"password" name=​"password" class=​"inputbox" size=​"18" title=​"Password" value=​"Password" onblur=​"if(this.value=='')​ this.value='Password';​" onfocus=​"if(this.value=='Password')​ this.value='';​">​ <input id=​"modlgn-passwd" type=​"password" name=​"password" class=​"input-small" tabindex=​"0" size=​"18" placeholder=​"Password">​


[Abatap]

Same issue with the date field js popup here. It only shows year 2021 in it's year dropdown but when you actually pick a date it shows the current year in the input field itself. VM 3.2.12, PHP 7.0.21 (behaves the same on PHP 7.1), Joomla 3.8.5. No any 3rd party plugin or template for VM is used.