Its not an error. It happens because automatic update has been configured in the plesk panel. Check in the Upgrades and Updates setting subsection in the Tools and Setting main section to see what configuration has been used in it.
Its always good to be updated, as bugs are fixed in the new releases. Anyway, as I have mentioned, you can check the upgrades and updates settings subsection to untick automatic update and keep it to something like manual update with notification or something like that, so it will let you know when the updates are available.