Is it happening for particular products? I can suspect un/reinstall of the product extension file.
Just the deployment\update tasks. Are you saying that extension un\reinstall could cause that or are you suggesting it as a solution? I doubt that the extension was un/reinstalled recently.
I'm also looking for a policy that not more exists....... and I'm sure that nobody has deleted them ! Seem so since 4.6 Patch3 we have a ghost in the console.....