When a user tries to log in the shopping cart, it sends the user to another url

[brassens]

Hello,
After update to VM 3.2.2 I have this problem. When a user tries to log in the shopping cart, after addition a product, the user is sent to another url, out of shopping cart. I have Joomla 3.7.3 with the template Epimeteo. I had the same problem two years ago when I had Joomla 3.4.5 and VM 3.0.10, but it was solved when we update to VM 3.0.12 (I think so). Now the same problem come back. I try with different PHP versions, but the error persist.
(The template use also a rokbox extension, a login popup.)

Thanks for your help
https://www.cortinaestor.es

[Milbo]

the value "return" keeps the return url base64 encoded

<input type="hidden" name="return" value="aW5kZXgucGhwP29wdGlvbj1jb21fdmlydHVlbWFydCZ2aWV3PWNhcnQmZm9ybWF0PWh0bWwmbGltaXRzdGFydD0wJmxpbWl0PTIwJmxhbmd1YWdlPWVzLUVTJm1hbmFnZT0wJkl0ZW1pZD0xMTkmbGFuZz1lcy1FUw==">

and points in your case to index.php?option=com_virtuemart&view=cart&format=html&limitstart=0&limit=20&language=es-ES&manage=0&Itemid=119&lang=es-ES and this one
https://www.cortinaestor.es/index.php?option=com_virtuemart&view=cart&format=html&limitstart=0&limit=20&language=es-ES&manage=0&Itemid=119&lang=es-ES
seems to lead me to your cart. You can check yourself the login form return value in the register/enter address form. Could also help to update to the last version (vm3.2.3) https://dev.virtuemart.net