Windows 10 PC Credential Manager losing password after restart

Dear admins,

I have been in the tech field for more than 4 years. But I have not seen this issue yet. There problem is I have one computer in my office which keep loosing its stored password on the credential manager.

Why do I need to store password on the Credential Manager?

We have a Synology NAS in our office unfortunately which is not connected to our domain. So, this make us to maintain separate usernames and password for all the domain users and departments.

How do we deploy Synology NAS password to the end users?

Since, we have domain with the version of Windows server 2012. We use have a PowerShell script which contains the required usernames and password for the users. Which we deploy on the startup using Group Policy option.

So, when user start their PC basically PowerShell update the credential on the computer. Here is the problem we have a condition in the PowerShell script to only updates the Passwords if changed. So, this computer some how loss the password while shutdown and does not contain the password after the next restart.

Please anyone guide me any suggestions beside Windows Upgrade.