NX Server App suddenly with extreme delays

Hi, I have a Dell 15th Gen Server running NX 6.1.2.42921 at a site with 60 cameras. The video client for this is a 13th Gen i9 with NVMe SSD, 32GB RAM and RTX 5060 Ti video card running 4 screens in low-res mode, Windows 11 Pro, at another site connected via VPN. For security reasons, there is no outside access to it, no connection to internet. It has been working normally including since upgrading to this latest version shortly after it came out. 

Suddenly yesterday the client started having big lags, not able to maintain several streams on the layouts, not able to send a soft trigger through it to open a gate which it normally does no problems, huge lags trying to pull up and review footage. 

This did not appear to be coincident with any environmental event and no software or hardware change had been done in recent days on either the Client or Server. 

This went on for a few hours before I arrived to shift. 

I rebooted the client but this made no difference. 

Our IT Chief checked the network line and confirmed it was normal, no issues. 

I tried to log into the NX Server App remotely and it was lagging (3 dots), not logging in. 

Using the client I then logged in remotely with Remote Desktop to the Server Windows OS (Windows Server 2022 Standard), which was lightning fast and responding normally. The Server OS drive had 415GB unused space. 

I stopped the NX Server App then about a minute later restarted the NX Server App. Immediately the client resumed operating normally, no issues at all, completely responsive without any lags. 

My concern is if the same thing might randomly happen tomorrow or soon, if there is something which might need to be remedied in the Server App. 

The NX Server was set to Info level logging. I've got the log which I can send.