What is [ERR] ULK?

Only seeing these on my Channels DVR TVE server, not my Channels DVR HDHR Prime server.
One in my log from last night while Channels DVR was completely idle.

[ERR] ULK response: 502 Bad Gateway

Another right before my DNS provider failed for about 4 minutes.

[ERR] ULK failure: Get "https://content-ause1-up-vod1.uplynk.com/session/ping/05b85d6492e24c6880861873e3c78a47.json?v=3&pt=9662": context deadline exceeded (Client.Timeout exceeded while awaiting headers)

I imagine "ULK" is a reference to Uplynk, which is a streaming video CDN (akin to Akamai) owned by Verizon. There errors look like either their server was down, or some other network issue.

This was in the log last night when nothing was happening on the Channels DVR server.

So it doesn't make sense to me why an error response is being received if Channels DVR isn't doing anything (at least nothing appearing in the log).

Are you sure no TVE streams were active at that time?

Yep. Had ended a short LIVE viewing of a TVE channel about 8 minutes before that error appeared. Nothing in the logs after it until this morning when a scheduled TVE recording started.

I just now wiped out that installation of v2020.07.22.2038 I was running and did a fresh install of v2020.07.30.2221

Still would like to know what ULK stands for if anyone knows.