I eventually replaced Spectrum's WiFi 6 router with an Asus RT-AX86S to absolutely rule out WiFi performance. Further, we've run the ATV furthest from our router using an Ethernet cable for several days, and found no difference in the Spectrum app's performance. Our issues described above exist despite high internet speed (WiFi to the ATVs is between 80-500 Mbps and latency is never slower than about 23 ms). In both cases, the Roku Stick played the recording, no issue. As for ACD-9000, we've found it to be either permanent or transitory (as happened today). My solution: watch with a Roku Stick or with Samsung TV! However, with those devices, you lose the ability to preview in FF and RWD. It happened three times in the last month. This seems to follow unusually long buffering times. Inability to play some recordings (ACD-9000 error).The Apple TV 4K then resumes on the spot at which I left off with the PC. When this happens with long recordings, I will reposition my place in the recording using a PC (where one can drag the progress bar to a known time hack - much faster than slogging at 4X FF through one to several hours of a recording). Unintentioinal reversion to beginning of a recording (goes hand-in-hand with prior item, Resume Recording).This is a daily occurrence, seems worse with longer recordings. Frequent loss of preview during FF or RWD, with need to step out of menu and back into My Library / Resume.Blurry images (from a few seconds to nearly a minute), associated with buffering (the spinning icon) this artifact occurs following RWD or FF.The issues below are intermittent (but not so intermittent that we are free of issues on any given day): Interesting to note that a 2017 model Apple TV that we borrowed from our daughter (before buying the others) allowed preview and was faster than the Roku Stick! We abandoned the Samsung Smart TV app and the Roku Stick Plus early on because they a) are slow (long buffering times) and b) cannot preview images during FF and RWD. Our three TVs are connected through ATV 4K boxes (two 2021 models, one is 2022).
We watch all content via recordings that are either in-progress or completely recorded for the simple reason that pause, RWD, and FF are unavailable in Live TV. Or, connect the router to the ATV with an Ethernet cable (if your ATV device has an Ethernet socket) to rule out bandwidth and latency. You may want to relocate the ATV to a set that is closer to your wireless router. You can check that by downloading the Ookla App to your ATV and running it when you see these issues. If have these issues while watching live TV, you may have an issue with your Internet (bandwidth on the ATV, or latency). We have similar issues with the Spectrum streaming app, but only when we watch recordings (see below). I'll assume you are watching recordings, not Live TV.