Deleting a user can affect a shared folder if the user was the admin of the folder. It's also worth mentioning that deleting a user that still has a linked personal account can result in complications for the user. It's best to have them unlink their personal account first.
"Whether a user account is deleted, disabled, or removed from theLastPass Businessaccount, this will not impact any remaining users or their previously associated shared folders. However, if the departed user was the admin of a shared folder, that folder will be left without an admin. For this reason, it is recommended that you enable the "Permit super admins to access shared folders" policy for at least one admin.
As a best practice and an added precaution, we suggest that any shared credentials be changed upon the departure of an employee, regardless of how you choose to manage their exit from LastPass. These changes to any shared folder will automatically sync to all assigned users, and this will give you an added layer of security."