So I have just started using Channels DVR and its great compared to others I've tried. So when I'm using either 4k Fire Stick or Nvidia Shield and remote to the DVR with settings at 4Mb 720p I can start watching a recording and scrub forward and back to wherever I want and everything works fine. After watching for around 5 minutes if I scrub backward past the buffer, like 20 minutes or so the unit will never recover playing. Backing out to the menu and hitting watch again fixes the issue easily and quickly. Backing out and starting it again remembers the position that I was trying to scrub back to, and that effectively allows me to continue to scrub to wherever I want until I've been watching for 5 minutes or more again. The playback freeze only happens when going backwards, forwards always works including skipping commercials. It happens on a 2015 shield TV and a 2018 (brand new) 4k Fire Stick, but not on my ipad IOS. As I said it only happens after watching for 5 minutes or so then going backwards past the buffer, and I'm remote to the DVR with a 10 Mb speed, 40 ms ping, 6 ms jitter. I tried hardware and software decoders on the shield, and hardware and software encoders on the server. Sometimes I get an audio squeal after playback locks up but I think if the playback would start again it would fix that too.
G5500 8th gen Intel CPU with iGPU
8 GB Ram
3.5" 7200 RPM 2 TB Internal Harddrive
2015 Nvidia Shield
2018 4K Fire Stick
Iphone and Ipad
Edit: Just wanted to clarify that this issue happens every time on the two android TV clients and is easily reproducible.