Sluggish server for 2 days after approving patches

I'm encountering an unusual issue and would like to know if others have experienced something similar.

I typically use the "Test and Approve" workflow for patch deployment, but late last week I manually approved patches for a workstation group of approximately 2,300 Windows machines. I'm currently using the latest version of Vulnerability Manager Plus.

I use automated policies to deploy patches, but I also have a policy to put all approved patches into the Portal so that users can install them at anytime.

For the next two days, I noticed:

A dcnginx.exe process consistently used 25% CPU. (This VM has 4 vCPUs, suggesting the process was maxing out a single core.)
The dashboard was very sluggish.
There was network activity to the workstations, which I figured to mean that it was copying patches, but it was not a lot. It was usually around 300-400Mbps utilization. I know that our infrastructure can do a lot more. (I used to run a WSUS server that would easily push 1-1.5Gbps over the network on Patch Tuesday.)
Disk activity was negligible.

After a couple days, the symptoms went away which I'm assuming that was because most of the patches finished copying.

Here is my theory: Something makes dcnginx bound to the speed of a single core while it was copying the patches to the workstations which slowed it down to <400Mbps and bogged down the whole server. When it completed copying most of the patches, the symptoms disappeared.

Has anyone encountered this or did I misconfigure something?