magento2.4.1 – Magento 2.4.1 PHP Fatal error: Allowed memory size of 2147483648 bytes exhausted (tried to allocate 176128 bytes)

This error(Allowed memory size of 2147483648 bytes exhausted (tried to allocate 20480 bytes) in vendor/magento/framework/Serialize/Serializer/Json.php on line 37) is populated when we access the category page (this category is top level category which shows all products (we have only 20-24 configurable products)). Not each time but it come after 10-12 days interval on the production environment.

We recently upgraded our server memory from 4g to 8g to solve this issue but it is still there.

We use nginx and php-fpm

We also updated the memory limit from .user.ini file from both the location m2 root and Pub

Thanks in advance.