Change in 2.5.920 behaviour, for proper request notification processing, even though a user with PAC permissions does not require approvals there must still be enough approvers available based on the current settings for the account or file being requested.
From the 2.5.920 release notes
PAC (Privileged Access) users allowed to request and access password, even if the number of required approvers for the account are not assigned. "
From the Administrator Guide:
"With a PAC permission type, the user must go through the request process for passwords, files, and sessions but after they submit the request it is automatically approved, regardless of the number of approvers required.
Even though a user with PAC permissions does not require approvals, there must still be enough approvers configured to approve the request, based on the required approvals settings for the account."