90 second lag at media playback start

Using Nvidia Shield as DVR client and server, Synology DS220j for DVR storage. Using HomeRun Prime 3 tuner as channels source. All 3 devices connected to router via cat5e, running at 1000 mbps. This works all over the house with different clients and even using the Channels DVR app on the Shield, it's magic. The only glitch I have is that when I use the Channels app on the Shield, and only to watch media recorded by the Channels DVR app on the Shield, there is a consistently reproducible 90 (or very occasionally 30) second delay waiting for the media to begin playing. Spinning circle under the playback progress bar. Never 60, nearly always 90, sometimes 30. Using the Channels clients anywhere else but the Shield, this doesn't happen. You guys are good, so I'm asking - anyone seen that, or have an idea what I should look for? It seems to be some kind of timeout or timed process, beyond that, I don't know what to do.

Strange. Can you click Settings > DVR > Speed Test and post the results?

Thanks.

Download: 2041.51 Mbit/s Latency: 0.96 ms Jitter: 0.53

The 2 Gbps speed isn't really indicative of performance. (Server and client run on the Shield, but the recordings live on the NAS.)
Additional: This particular problem began when I got the Synology set up to be the storage for DVR. I had a 1TB external SSD connected to the Shield before and it worked, but I had to make Shield remount the drive a lot. Using the NAS is much better, but I wondered if this 90 second playback start delay is something someone else had noticed. It's probably the NAS itself causing it, and I'll pursue that too.

Stand down. It's fixed itself. I lost cable last night after midnight - suspect a maint window - and when I checked it this morning, it had Channels had lost the channel lineup. After I scanned the channels, recordings (made before losing cable) started right up. Very odd, but acceptable if it stays that way. Cheers, y'all.