On one of my sites when I have updates available for plugins I get a notification as usual. I update them using the WordPress updater. Whether I do the updates one by one or all together they always say updates are successful however when I go back to the plugins page the same plugins need updating still.
The only way of updating the plugins is to delete them from the plugins folder and then re-add the latest version of the plugin.
There are no issues with CHMOD permissions as far as I can see and I've also tried turning off all the plugins and then updating but no joy. I've also tried re-installing WordPress too but it doesn't help.
If anyone has any insight into what might be happening here I would really appreciate it.
The site is here.